Designing indacenodithiophene based non-fullerene acceptors with a donor-acceptor combined bridge for organic solar cells

Tuning the optoelectronic properties of selenophene-diketopyrrolopyrrole-based non-fullerene acceptor to obtain efficient organic solar cells through end-capped modification

With the goal of developing a high-performance organic solar cell, nine molecules of A2-D-A1-D-A2 type are originated in the current investigation. The optoelectronic properties of all the proposed compounds are examined by employing the DFT approach and the B3LYP functional with a 6-31G (d, p) basis set. By substituting the terminal moieties of reference molecule with newly proposed acceptor groups, several optoelectronic and photovoltaic characteristics of OSCs have been studied, which are improved to a significant level when compared with reference molecule, i.e., absorption properties, excitation energy, exciton binding energy, band gap, oscillator strength, electrostatic potential, light-harvesting efficiency, transition density matrix, open-circuit voltage, fill factor, density of states and interaction coefficient. All the newly developed molecules (P1-P9) have improved λmax, small band gap, high oscillator strengths, and low excitation energies compared to the reference molecule. Among all the studied compounds, P9 possesses the least binding energy (0.24 eV), P8 has high interaction coefficient (0.70842), P3 has improved electron mobility due to the least electron reorganization energy (λe = 0.009182 eV), and P5 illustrates high light-harvesting efficiency (0.7180). P8 and P9 displayed better Voc results (1.32 eV and 1.33 eV, respectively) and FF (0.9049 and 0.9055, respectively). Likewise, the phenomenon of charge transfer in the PTB7-Th/P1 blend seems to be a marvelous attempt to introduce them in organic photovoltaics. Consequently, the outcomes of these parameters demonstrate that adding new acceptors to reference molecule is substantial for the breakthrough development of organic solar cells (OSCs).

End-capped engineering of Quinoxaline core-based non-fullerene acceptor materials with improved power conversion efficiency

Improving the light-harvesting efficiency and boosting open circuit voltage are crucial challenges for enhancing the efficiency of organic solar cells. This work introduces seven new molecules (SA1-SA7) to upgrade the optoelectronic and photovoltaic properties of Q-C-F molecule-based solar cells. All recently designed molecules have the same alkyl-substituted Quinoxaline core and CPDT donor but vary in the end-capped acceptor subunits. All the investigated molecules have revealed superior properties than the model (R) by having absorbance ranging from 681 nm to 782 nm in the gaseous medium while 726 nm-861 nm in chloroform solvent, with the lowest band gap ranging from 1.91 to 2.19 eV SA1 molecule demonstrated the highest λmax (861 nm) in chloroform solvent and the lowest band gap (1.91 eV). SA2 molecule has manifested highest dipole moment (4.5089 D), lower exciton binding energy in gaseous (0.33 eV) and chloroform solvent (0.47 eV), and lower charge mobility of hole (0.0077693) and electron (0.0042470). At the same time, SA7 showed the highest open circuit voltage (1.56 eV) and fill factor (0.9166) due to solid electron-pulling acceptor moieties. From these supportive outcomes, it is inferred that our computationally investigated molecules may be promising candidates to be used in advanced versions of OSCs in the upcoming period.

Boosting the Performance of Diketopyrrolopyrrole-Triphenylamine-Based Organic Solar Cells via π-Linker Engineering

The design and development of novel and efficient donor-π-acceptor (D-π-A) type conjugated systems has attracted substantial interest in the field of organic electronics owing to their intriguing properties. In this paper, we have designed seven new and efficient D-π-A type conjugated systems (M1-M7) by a variety of π-linkers with triphenylamine (TPA) as the electron donor and diphenyldiketopyrrolopyrrole (DPP) as the electron acceptor using density functional theory (DFT) formalism for organic solar cells (OSCs). The π-linker has been substituted between the donor and acceptor for efficient electron transfer. Here, our primary focus is on narrowing the highest occupied molecular orbital-lowest unoccupied molecular orbital gaps, electronic transition, charge transfer rate, reorganization energies, and the theoretical power conversion efficiencies (PCEs). Our study reveals that the designed compounds exhibit excellent charge transfer rates. The absorption properties of the compounds have been examined using the time-dependent density functional theory (TD-DFT) method. The TD-DFT study shows that compound M2 possesses the highest absorption maxima with a maximum bathochromic shift. For a better understanding of the electron transport process of our designed compounds, we have designed donor/acceptor (D/A) blends, and each of the developed blends (FREA/M1-M7) can encourage charge carrier separation. According to the photovoltaic performance of the D/A blends, compound FREA-M2, which has a theoretical PCE of 16.53%, is the most appealing choice for use in OSCs. We expect that by thoroughly examining the relationship between structure, characteristics, and performance, this work will serve as a roadmap for future research and development of TPA-DPP-based photovoltaic materials.

An efficient end-capped engineering of pyrrole-based acceptor molecules for high-performance organic solar cells

CONTEXT

Various innovative molecules have been designed and explored for use in organic photovoltaics. In this study, we devised novel molecules (KZ1-KZ7) specifically for organic solar cells (OSCs). The newly formulated acceptor compounds possess a lower bandgap (Eg = 1.85-2.02), along with bathochromic shift (λmax = 713-788 nm) compared to the reference (Eg = 2.04 eV and λmax = 774 nm). Moreover, the FMO results identified the distinct charge transfer from HOMO to LUMO, which was strongly corroborated by the TDM maps. Similarly, the new designed molecules show less excitation energy (Ex = 1.31-1.54(gas)) than reference (Ex = 1.72). Likewise, all designed molecules (KZ1-KZ7) have demonstrated an analogous open circuit voltage (Voc) with the donor polymer PTB7-Th. All seven designed molecules (KZ1-KZ7) exhibited more fill factor ranging from 97.08 to 97.29 than reference 95.25 and PCE of between 8 and 20% at short circuit current densities of 9, 12, and 15 mA cm-2. Overall, the findings support that designed molecules can be potential molecules for future practical applications.

METHODS

Geometric calculations were conducted with Gaussian 09W software, and the findings were visualized using Gauss View software. DFT and TD-DFT were employed to evaluate various parameters for R and designed molecules (KZ1-KZ7). Firstly, four functionals including B3LYP, CAM-B3LYP, MPW1PW91, and ωB97XD with 6-31G(d,p) DFT level were applied to R to decide the best level for results. After appropriate analysis, the MPW1PW91/6-31G(d,p) was selected for further examination by comparing the experimental and DFT-based absorption graphs of R. External and internal reorganization energy are the two main factors contributing to reorganization energy. External energy refers to changes in external environment, while internal energy deals with information related to internal geometrical symmetry or the internal environment. The effect of outside factors or external reorganizational energy is omitted because it creates too little change.

Exploring the Electronic, Optical, and Charge Transfer Properties of A-D-A-Type IDTV-ThIC-Based Molecules To Enhance Photovoltaic Performance of Organic Solar Cells

Improving the charge mobility and optoelectronic properties of indacenodithiophene-based small molecule acceptors is a key challenge to improving overall efficiency. In this current research, seven newly designed molecules (DT1-DT7) comprising the indacenodithiophene-based core are presented to tune energy levels, enhance charge mobility, and improve the photovoltaic performance of IDTV-ThIC molecules via density functional theory. All the molecules were designed by end-capped modification by substituting terminal acceptors of IDTV-ThIC with strong electron-withdrawing moieties. Among all the examined structures, DT1 has proved itself a superior molecule in multiple aspects, including higher λmax in chloroform (787 nm) and gaseous phase (727 nm), narrow band gap (2.16 eV), higher electron affinity (3.31 eV), least excitation energy (1.57 eV), and improved charge mobility due to low reorganization energy and higher excited state lifetime (2.37 ns) when compared to the reference (IDTV-ThIC) and other molecules. DT5 also showed remarkable improvement in different parameters, such as the lowest exciton binding energy (0.41 eV), leading to easier charge moveability. The improved open-circuit voltage of DT4 and DT5 makes them proficient molecules exhibiting the charge transfer phenomenon. The enlightened outcomes of these molecules can pave a new route to develop efficient organic solar cell devices using these molecules, especially DT1, DT4, and DT5.

End-cap modeling on the thienyl-substituted benzodithiophene trimer-based donor molecule for achieving higher photovoltaic performance

Despite the substantial advancements in organic solar cells (OSCs), the best devices still have quite low efficiencies due to less focus on donor molecules. With the intention to present efficient donor materials, seven small donor molecules (T1-T7) were devised from DRTB-T molecule by using end-capped modeling. Newly designed molecules exhibited remarkable improved optoelectronic properties such as less band gap (from 2.00 to 2.23 eV) than DRTB-T having band gap of 2.57 eV. Similarly, a significant improvement in λmax values was noticed in designed molecules in gaseous medium (666 nm-738 nm) and solvent medium (691 nm-776 nm) than DRTB-T having λmax values at 568 nm and 588 nm in gas and solvent phase respectively. Among all molecules, T1 and T3 exhibited significant improvement in optoelectronic properties such as narrow band gap, lower excitation energy, higher λmax values and lower electron reorganization energy as compared to pre-existed DRTB-T molecule. The better functional ability of T1-T7 is also suggested by an improvement in open circuit voltage (Voc) of designed structures (1.62 eV-1.77 eV) as compared to R (1.49 eV) when PC61BM is used as an acceptor. So, all our newly derived donors can be employed in the active layer of organic solar cells to manufacture efficient OSCs.

Theoretical Perspective toward Designing of 5-Methylbenzo [1,2-b:3,4-b':6,5-b″] trithiophene-Based Nonlinear Optical Compounds with Extended Acceptors

A series of benzotrithiophene-based compounds (DCTM1-DCTM6) having D1-π1-D2-π2-A configuration were designed using a reference molecule (DCTMR) via incorporating pyrrole rings (n = 1-5) as the π-spacer (π2). Quantum chemical calculations were performed to determine the impact of the pyrrole ring on the nonlinear optical (NLO) behavior of the above-mentioned chromophores. The optoelectronic properties of the compounds were determined at the MW1PW91/6-311G(d,p) functional. Among all of the derivatives, DCTM5 exhibited the least highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO-LUMO) band gap (Eg) 0.968 eV with a high softness of 0.562 eV-1, and hence possessed the highest polarizability. Interestingly, transition density matrix (TDM) findings demonstrated that DCTM5 with an effective diagonal charge transmission proportion at the acceptor group supports the frontier molecular orbital (FMO) results. Additionally, the exciton binding energy values for DCTM1-DCTM6 were found to be less than that for DCTMR and thus, the effective charge transfer was examined in the derivatives. All of the derivatives exhibited effective NLO outcomes with the highest magnitude of linear polarizability ⟨α⟩, and first (βtot) and second (γtot) hyperpolarizabilities relative to the parent compound. Nevertheless, the highest βtot and γtot were obtained for DTCM1 and DTCM6, 7.0440 × 10-27 and 22.260 × 10-34 esu, respectively. Hence, through this structural tailoring with a pyrrole spacer, effective NLO materials can be obtained for optoelectronic applications.

Designing Y-shaped two-dimensional (2D) polymer-based donor materials with addition of end group acceptors for organic and perovskite solar cells

CONTEXT

For the advancement in fields of organic and perovskite solar cells, various techniques of structural alterations are being employed on previously reported chromophores. This way, molecules with all the properties desired for better performance of solar cells can be achieved. In this regard, theoretical modeling of chromophores has gained quite an interest due to its ability to save time, resources, and money. Herein, five new Y-shaped donor materials were theoretically engineered by adding electron-withdrawing acceptors on reported 2DP molecule. The results explored that, in comparison to 2DP, the produced molecules showed red shift in the absorption peaks, smaller bandgaps and binding energies, lower excitation potential, and greater dipole moment and were also highly reactive. When paired with PC₆₁BM, proposed compounds exhibited higher estimated power conversion efficiencies and open-circuit voltage in contrast to 2DP. Individually, 2DP1 possessed the largest conductivity of electrons and the maximum mobility of holes, due to its computed lowest reorganization energies. The results illustrate the viability of the proposed procedure, opening doors for the manufacturing of required solar cells with enhanced photovoltaic properties.

METHODS

Precisely, a DFT and TD-DFT analysis on 2DP and all of the proposed molecules was conducted, using the functional MPW1PW91 at 6-31G (d,p) basis set to examine their optoelectronic aspects; additionally, the solvent state computations were studied with a TD-SCF simulation. For all these simulations, Gaussian 09 and GaussView 5.0 were employed. Moreover, the Origin 6.0 software, Multiwfn 3.8 software, and PyMOlyze 1.1 software were utilized for the visual depiction of the graphs of absorption, TDM, and DOS, respectively, of the studied molecules. A number of crucial aspects such as FMOs, bandgaps, light-harvesting efficiency, electrostatic potential, dipole moment, ionization potential, open-circuit voltage, fill factor, binding energy, interaction coefficient, chemical hardness-softness, and electrophilicity index were also investigated for the studied molecules.

Designing of anthracene-arylamine hole transporting materials for organic and perovskite solar cells

This study focuses on the creation of 5 small donor molecules (A102W1-A102W5) by substituting the one-sided methoxy group of model (A102R) with different thiophene bridged acceptor moieties. B3LYP/6-31**G (d,p) model has been employed for computational analysis. The best miscibility was found for A102W3 in dichloromethane (DCM) solvent, where its λ_max was also found to be at 753 nm, its E_g was found to be 1.55 eV as well as dipole moment in DCM was 21.47 D. The percentage of PCE among all the variants was greatest for A102W2 (25.31%). The electron reorganization energy shown by A102W4 was 0.00470 eV, whereas the hole reorganization energy investigated in A102W2 was 0.00586 eV representing their maximum electron and hole mobility respectively amongst all. Results validate the value of specified techniques, opening a new door to create efficient small donors for OSCs and HTMs for PSCs.

Designing of Thiophene [3, 2-b] Pyrrole Ring-Based NFAs for High-Performance Electron Transport Materials: A DFT Study

Among the blended components of a photoactive layer in organic photovoltaic (OPV) cells, the acceptor is of high importance. This importance is attributed to its increased ability to withdraw electrons toward itself for their effective transport toward the respective electrode. In this research work, seven new non-fullerene acceptors were designed for their possible utilization in the OPVs. These molecules were designed through side-chain engineering of the PTBTP-4F molecule, with its fused pyrrole ring-based donor core and different strongly electron-withdrawing acceptors. To elucidate their effectiveness, the band gaps, absorption characteristics, chemical reactivity indices, and photovoltaic parameters of all of the architecture molecules were compared with the reference. Through various computational software, transition density matrices, graphs of absorption, and density of states were also plotted for these molecules. From some chemical reactivity indices and electron mobility values, it was proposed that our newly designed molecules could be better electron-transporting materials than the reference. Among all, TP1, due to its most stabilized frontier molecular orbitals, lowest band gap and excitation energies, highest absorption maxima in both the solvent and gas medium, least hardness, highest ionization potential, superior electron affinity, lowest electron reorganization energy, as well as highest rate constant of charge hopping, seemed to be the best molecule in terms of its electron-withdrawing abilities in the photoactive layer blend. In addition, in terms of all of the photovoltaic parameters, TP4-TP7 was perceived to be better suited in comparison to TPR. Thus, all our suggested molecules could act as superior acceptors to TPR.

Enhancing the Photovoltaic Properties via Incorporation of Selenophene Units in Organic Chromophores with A2-π2-A1-π1-A2 Configuration: A DFT-Based Exploration

Currently, polymer organic solar cells (POSCs) are widely utilized due to their significant application, such as low-cost power conversion efficiencies (PCEs). Therefore, we designed a series of photovoltaic materials (D1, D2, D3, D5 and D7) by the incorporation of selenophene units (n = 1-7) as π₁-spacers by considering the importance of POSCs. Density functional theory (DFT) calculations were accomplished at MPW1PW91/6-311G (d, p) functional to explore the impact of additional selenophene units on the photovoltaic behavior of the above-mentioned compounds. A comparative analysis was conducted for designed compounds and reference compounds (D1). Reduction in energy gaps (∆E = 2.399 - 2.064 eV) with broader absorption wavelength (λ_max = 655.480 - 728.376 nm) in chloroform along with larger charge transference rate was studied with the addition of selenophene units as compared to D1. A significantly higher exciton dissociation rate was studied as lower values of binding energy (E_b = 0.508 - 0.362 eV) were noted in derivatives than in the reference (E_b = 0.526 eV). Moreover, transition density matrix (TDM) and density of state (DOS) data also supported the efficient charge transition origination from HOMOs to LUMOs. Open circuit voltage (V_oc) was also calculated for all the aforesaid compounds to check the efficiency, and significant results were seen (1.633-1.549 V). All the analyses supported our compounds as efficient POSCs materials with significant efficacy. These compounds might encourage the experimental researchers to synthesize them due to proficient photovoltaic materials.

Theoretical framework for achieving high V oc in non-fused non-fullerene terthiophene-based end-capped modified derivatives for potential applications in organic photovoltaics

Non-fused ring-based OSCs are an excellent choice, which is attributed to their low cost and flexibility in applications. However, developing efficient and stable non-fused ring-based OSCs is still a big challenge. In this work, with the intent to increase V _oc for enhanced performance, seven new molecules derived from a pre-existing A-D-A type A3T-5 molecule are proposed. Different important optical, electronic and efficiency-related attributes of molecules are studied using the DFT approach. It is discovered that newly devised molecules possess the optimum features required to construct proficient OSCs. They possess a small band gap ranging from 2.22-2.29 eV and planar geometries. Six of seven newly proposed molecules have less excitation energy, a higher absorption coefficient and higher dipole moment than A3T-5 in both gaseous and solvent phases. The A3T-7 molecule exhibited the maximum improvement in optoelectronic properties showing the highest λ _max at 697 nm and the lowest E _x of 1.77 eV. The proposed molecules have lower ionization potential values, reorganization energies of electrons and interaction coefficients than the A3T-5 molecule. The V _oc of six newly developed molecules is higher (V _oc ranging from 1.46-1.72 eV) than that of A3T-5 (V _oc = 1.55 eV). Similarly, almost all the proposed molecules except W6 exhibited improvement in fill factor compared to the A3T-5 reference. This remarkable improvement in efficiency-associated parameters (V _oc and FF) proves that these molecules can be successfully used as an advanced version of terthiophene-based OSCs in the future.

In Silico Designing of Thieno[2,3-b]thiophene Core-Based Highly Conjugated, Fused-Ring, Near-Infrared Sensitive Non-fullerene Acceptors for Organic Solar Cells

The performance of organic solar cells (OSCs) has been improving steadily over the last few years, owing to the optimization of device fabrication, fine-tuning of morphology, and thin-film processing. Thiophene core containing fused ring-type non-fullerene acceptors (NFAs) achieved significant proficiency for highly efficient OSCs. Quantum chemical computations are utilized herein with the motive of suggesting new NIR sensitive, highly efficient low-band gap materials for OSCs. A series of extended conjugated A-π-D-π-A architectured novel fused-ring NFAs (FUIC-1-FUIC-6) containing thieno[2,3-b]thiophene-based donor core are proposed by substituting the end-capped units of synthesized molecule F10IC. Different properties including frontier molecular orbital analysis, density of states analysis, transition density matrix analysis, excitation energy, reorganizational energies of both holes (λ_h) and electrons (λ_e), and open-circuit voltage (V _oc) were performed employing the density functional theory approach. Charge transfer analysis of the best-designed molecule with the donor complex was analyzed to comprehend the efficiency of novel constructed molecules (FUIC-1-FUIC-6) and compared with the reference. End-caped acceptor alteration induces the reduction of the energy gap between HOMO-LUMO (1.88 eV), tunes the energy levels, longer absorption in the visible and near-infrared regions, larger V _oc, smaller reorganizational energies, and binding energy values in designed structures (FUIC-1-FUIC-6) in comparison to reference (FUIC). The designed molecules show the best agreement with the PTBT-T donor polymer blend and cause the highest charge from the HOMO to the LUMO orbital. Our findings predicted that thieno[2,3-b] thiophene-based newly designed molecules would be efficient NFAs with outstanding photovoltaic characteristics and can be used in future applications of OSCs.

Computational Investigation of Near-Infrared-Absorbing Indeno[1,2-b]indole Analogues as Acceptors in Organic Photovoltaic Devices

Organic solar cells (OSCs) with fullerene-free acceptors have recently been in high demand in the solar cell market because OSCs are less expensive, more flexible, long-lasting, eco-friendly, and, most importantly, have better photovoltaic performance with a higher PCE. We used INTIC as our reference R molecule and designed five new molecules DF1-DF5 from this R molecule. We attempted to test the power conversion efficiencies of five designed novel molecules, DF1-DF5. Therefore, we compared the PCE values of DF1-DF5 with that of R. We used a variety of computational techniques on these molecules to achieve this goal. Among the designed molecules, DF5 proved to be the best due to its lowest H-L bandgap energy E _g (1.82 eV), the highest value of λ_max (844.58 nm) within dichloromethane, the lowest excitation energy (1.47 eV), and the lowest oscillator strength value. The newly designed molecule DF2 exhibited the highest dipole moment (21.98 D), while DF3 displayed the minimum binding energy (0.34 eV) and the highest V _oc value (1.37 V) with HOMO_donor-LUMO_acceptor. According to the partial density of states (PDOS) and transition density matrix (TDM) analysis, DF2 and DF5 exhibited the best results. Charge-transfer (CT) analysis of the blend DF5 and PTB7-Th confirmed the accepting nature of the DF5 molecule. These findings show that by modifying the end-capped units, we can create customized molecules with improved photovoltaic properties. These findings also show that when compared with R, all of the designed molecules DF1-DF5 have improved optoelectronic properties. As a result, it is strongly advised to employ these conceptualized molecules in the practical synthesis of organic solar cells (OSCs).

Toward Quantifying the Relation between Exciton Binding Energies and Molecular Packing

Reducing the exciton binding energy E_b of organic photoactive materials is critical to minimize the energy loss and improve the photovoltaic efficiency of organic solar cells. However, the relation between the E_b and molecular packing is not well understood. Herein, the E_b in the crystals of a series of A-D-A type nonfullerene acceptors with different lengths of alkyl side chains has been examined by self-consistent quantum mechanics/embedded charge calculations. The variation of molecular packing induced by the different alkyl chains can have an important impact on the polarization effect of charge carriers and thereby the E_b. More interestingly, the E_b values are found to be linearly increased with the ratio of the void fraction vs the packing coefficient of molecular backbones in the solid crystals. Owing to the smallest ratio, a remarkable low E_b of several tens of meV is achieved for the acceptor with an optimal length of alkyl chains.

First theoretical framework for highly efficient photovoltaic parameters by structural modification with benzothiophene-incorporated acceptors in dithiophene based chromophores

Now a days, researchers are constantly doing efforts to upgrade the performance of solar based devices with the aim of increasing the role of photovoltaic materials in modern hi-tech optoelectronic applications. Realizing the recent energy conditions across the globe, research is diverted from fullerene to non-fullerene electron acceptor moieties in this era, considering their remarkable contribution in organic solar cells (OSCs). Therefore, we designed seven novel non-fullerene fused ring electron acceptor chromophores (MD2-MD8) from DOC2C6-2F by structural tailoring with different acceptors at end-capped units. DFT study was performed at B3LYP functional to discover the opto-electronic characteristics of the newly tailored chromophores. Various analysis such as frontier molecular orbitals (FMOs), transition density matrix (TDM), density of states (DOS), binding energy (Eb), reorganization energy, open circuit voltage (Voc) was carried out to comprehend the photovoltaic response of MD2-MD8. Decrease in band gaps (1.940-1.571 eV) with wider absorption spectrum (725.690-939.844 nm in chloroform) along with greater charge transfer rate from HOMO towards LUMO were examined in derivatives as compared to MR1 (Egap = 1.976 eV, λmax = 738.221 nm) except MD7. Further, in all derivatives, smaller values of Eb (0.252-0.279 eV) were examined than that of reference (0.296 eV). These lower binding energy values of MD2-MD8 indicated the higher rate of excitation dissociation with lager charger transfer rate than MR1, which further supported by DOS and TDM analyses. Additionally, least reorganization energy in the aforesaid compounds for hole with electron was also inspected. Moreover, Voc a good photovoltaic response was noted for all studied compounds which indicated that these compounds are suitable to synthesize OSCs in future.

Impact of end-group modifications and planarity on BDP-based non-fullerene acceptors for high-performance organic solar cells by using DFT approach

With the aim to enhance the photovoltaic properties of organic solar cells (OSCs), seven new non-fullerene acceptors (K1-K7) have been designed by end-group modifications of benzo[2,1-b:3,4-b']bis(4H-dithieno[3,2-b:2',3'-d]pyrrole) (BDP)-based small molecule "MH" (which is taken as our reference R) using computational techniques. To investigate their various optoelectronic parameters, DFT studies were applied using the B3LYP functional at 6-31G (d, p) basis set. The measurement of molecular planarity parameter (MPP) and span of deviation from plane (SDP) confirmed the planar geometries of these structures resulting in enhanced conjugation. Frontier molecular orbital (FMO) and density of states (DOS) analyses confirmed shorter band gaps of K1-K7 as compared to R, which promotes charge transfer in them. Optical properties demonstrated that these compounds have absorption range from 692 to 711 nm, quite better than the 684 nm of reference R. Molecular electrostatic potential (MEP) and Mulliken' charge distribution analysis also revealed the presence of epic charge separation in these structures. K1-K7 showed enhanced LHE values as compared to R putting emphasis on their better abilities to produce charge carrier by absorption of light. Reorganization energies showed that all newly designed compound could have better rate of charge carrier mobility (except K4) than R. Calculations of open-circuit voltage (V_oc) and fill factor (FF) revealed its highest values for K3 and K4. Among newly designed molecules, K3 showed betterment in all its investigated parameters, making it a strong candidate to get enhanced power conversion efficiencies of OSCs.

Impact of end-capped modification of MO-IDT based non-fullerene small molecule acceptors to improve the photovoltaic properties of organic solar cells

Density functional theory, along with its time dependent computational approach were employed in order to fine tune the photovoltaic attributes along with the efficiency of the MO-IDIC-2F molecule. Thus, five new molecules were designed by substitution of the different notable acceptor fragments in the MO-IDIC-2F molecule, along with the addition of the "[1, 2, 5] thiadiazolo[3,4-d] pyridazine" spacer moieties between donor core and newly substituted acceptor groups. In this research work, various photovoltaic properties, which could affect the efficiency of an organic chromophores, such as bandgap, oscillator strength, dipole moment, binding energy, light-harvesting efficiency, etc. were studied. All the newly proposed molecules demonstrated significantly improved outcomes in comparison to that of the reference molecule, in their absorption spectrum, excitation, as well as binding energy values, etc. In order to confirm the results of optoelectronic properties, density of states, transition density matrix, and electrostatic potential analyses of molecules were also performed, which supported our computational findings. All of the results confirmed the high potential of all the newly proposed molecules for the development of improved OSCs.

Designing dibenzosilole core based, A2-π-A1-π-D-π-A1-π-A2 type donor molecules for promising photovoltaic parameters in organic photovoltaic cells

In this research work, four new molecules from the π-A-π-D-π-A-π type reference molecule "DBS-2PP", were designed for their potential application in organic solar cells by adding peripheral A2 acceptors to the reference. Under density functional theory, a comprehensive theoretical investigation was conducted to examine the structural geometries, along with the optical and photovoltaic parameters; comprising frontier molecular orbitals, density of states, light-harvesting effectiveness, excitation, binding, and reorganizational energies, molar absorption coefficient, dipole moment, as well as transition density matrix of all the molecules under study. In addition, some photo-voltaic characteristics (open circuit photo-voltage and fill factor) were also studied for these molecules. Although all the developed compounds (D1-D4) surpassed the reference molecule in the attributes mentioned above, D4 proved to be the best. D4 possessed the narrowest band-gap, as well as the highest absorption maxima and dipole moment of all the molecules in both the evaluated phases. Moreover, with PC61BM as the acceptor, D4 showed the maximum V OC and FF values. Furthermore, while D3 had the greatest hole mobility owing to its lowest value of hole reorganization energy, D4 exhibited the maximum electron mobility due to its lowermost value of electron reorganization energy. Overall, all the chromophores proposed in this study showed outstanding structural, optical, and photovoltaic features. Considering this, organic solar cell fabrication can be improved by using these newly derived donors at the donor-acceptor interfaces.

Efficient All-Polymer Solar Cells Enabled by Interface Engineering

All-polymer solar cells (all-PSCs) are organic solar cells in which both the electron donor and the acceptor are polymers and are considered more promising in large-scale production. Thanks to the polymerizing small molecule acceptor strategy, the power conversion efficiency of all-PSCs has ushered in a leap in recent years. However, due to the electrical properties of polymerized small-molecule acceptors (PSMAs), the FF of the devices is generally not high. The typical electron transport material widely used in these devices is PNDIT-F3N, and it is a common strategy to improve the device fill factor (FF) through interface engineering. This work improves the efficiency of all-polymer solar cells through interfacial layer engineering. Using PDINN as the electron transport layer, we boost the FF of the devices from 69.21% to 72.05% and the power conversion efficiency (PCE) from 15.47% to 16.41%. This is the highest efficiency for a PY-IT-based binary all-polymer solar cell. This improvement is demonstrated in different all-polymer material systems.

Theoretical studies on donor-acceptor based macrocycles for organic solar cell applications

We have designed a series of new conjugated donor-acceptor-based macrocyclic molecules using state-of-the-art computational methods. An alternating array of donors and acceptor moieties in these macrocycle molecules are considered to tune the electronic and optical properties. The geometrical, electronic, and optical properties of newly designed macrocyclic molecules are fully explored using various DFT methods. Five conjugated macrocycles of different sizes are designed considering various donor and acceptor units. The selected donor and acceptors, viz., thiophene (PT), benzodithiophene (BDT), dithienobenzodithiophene (DTBDT), diketopyrrolopyrrole (DPP), and benzothiazole (BT), are frequently found in high performing conjugated polymer for different organic electronic applications. To fully assess the potential of these designed macrocyclic derivatives, analyses of frontier molecular orbital energies, excited state energies, energy difference between singlet-triplet states, exciton binding energies, rate constants related to charge transfer at the donor-acceptor interfaces, and electron mobilities have been carried out. We found significant structural and electronic properties changes between cyclic compounds and their linear counterparts. Overall, the cyclic conjugated D-A macrocycles' promising electronic and optical properties suggest that these molecules can be used to replace linear polymer molecules with cyclic conjugated oligomers.

Spirothienoquinoline-based acceptor molecular systems for organic solar cell applications: DFT investigation

In this research, eight three-dimensional benzothiadiazole and spirothienoquinoline-based donor molecules of the A-D-A-D-A configuration were formulated by introducing new acceptor groups (A1-A4) to the terminal sites of recently synthesized potent donor molecule (^tBuSAF-Th-BT-Th-^tBuSAF). Frontier molecular orbital analysis, reorganization energies, the density of states analysis, transition density matrix analysis, dipole moment, open-circuit voltage, and some photophysical properties were all assessed using CAMB3LYP/LanL2DZ. The optoelectronic properties of freshly proposed compounds were compared to the reference molecule (SQR). Due to the existence of robust electron-attracting acceptor moiety, SQM3 and SQM7 had the greatest maximum absorption of all other investigated molecules, with the values of 534 and 536 nm, respectively. The maximum dipole moment, narrow bandgap (3.81 eV and 3.66 eV), and HOMO energies (- 5.92 eV, 5.95 eV) are also found in SQM3 and SQM7, respectively. The SQM3 molecule also possesses the least reorganization energy for hole mobility (0.007237 eV) than all other considered molecules. The open-circuit voltage of all the molecules considered to be donors, was calculated with respect to PC₆₁BM and it is estimated that except SQM7 and SQM3 all other newly developed molecules have improved open-circuit voltage. The findings show that most of the designed donor molecules can perform better experimentally and should be employed for practical implementations in the future.

Tuning of a A-A-D-A-A-Type Small Molecule with Benzodithiophene as a Central Core with Efficient Photovoltaic Properties for Organic Solar Cells

With the aim of upgrading the power conversion efficiency of organic solar cells (OSCs), four novel non-fullerene, A1-A2-D-A2-A1-type small molecules were designed that are derivatives of a recently synthesized molecule SBDT-BDD reported for its efficient properties in all-small-molecule OSCs (ASM-OSCs). Optoelectronic properties of the designed molecules were theoretically computed with a selected CAM-B3LYP functional accompanied by the 6-31G(d,p) basis set of density functional theory (DFT), and excited-state calculations were performed through the time-dependent self-consistent field. The parameters of all analyzed molecules describing the charge distribution (frontier molecular orbitals, density of states, molecular electrostatic potential), absorption properties (UV-vis absorption spectra), exciton dynamics (transition density matrix), electron-hole mobilities (reorganization energies), and exciton binding energies were computed and compared. All the designed molecules were found to be superior regarding the aforesaid properties to the reference molecule. Among all molecules, SBDT1 has the smallest band gap (3.88 eV) and the highest absorption maxima with broad absorption in the visible region. SBDT3 has the lowest binding energy (1.51 eV in chloroform solvent) ensuring easier and faster dissociation of excitons to produce free charge-carriers and has the highest open-circuit voltage (2.46 eV) with PC61BM as the acceptor. SBDT1 possesses the highest hole mobility because it has the lowest value of λ+ (0.0148 eV), and SBDT4 exhibits the highest electron mobility because it has the lowest value of λ- (0.0146 eV). All the designed molecules are good candidates for ASM-OSCs owing to their superior and optimized properties.

Designing and theoretical study of fluorinated small molecule donor materials for organic solar cells

A recently synthesized photoactive donor named fluorinated thienyl-substituted benzodithiophene (DRTB-FT), modified with four novel end capped acceptor molecules, has been investigated through different electrical, quantum, and spectrochemical techniques for its enhanced electro-optical and photovoltaic properties. DRTB-FT was connected to 2-methylenemalononitrile (D-1), 2-methylene-3-oxobutanenitrile (D-2), 2-(2-methylene-3-oxo-2,3-dihydro-1H-inden-1-ylidene) malononitrile (D-3), and 3-methyl-5methylene-2-thioxothiazolidin-4-one (D-4) as terminal acceptor moieties. The architectural D-1 and D-3 molecules owe reduced optical band gap of 2.45 and 2.28 eV benefited from A-D-A configuration and have broaden maximum absorption band (λ_max) at 617 and 602 nm in polar organic solvent (chloroform). Reduced optical band gap sets the ease for enhanced absorption. Reorganization energy of electron (λ_e) of D-3 molecule (0.00397 eV) was smaller among all which disclosed its greater mobility of conducting electrons (ICT). Larger values of dipole moment (μ) of D-1 (5.939 Debye) and D-3 (3.661 Debye) molecules in comparison to R indicated greater solubilities of the targeted molecules. Among the tailored molecules, D-3 showed the lowest binding energy of 0.25 eV in solvent phase and 0.08 eV in gaseous phase. The voltaic strength of the designed molecules was examined with respect to fullerene derivative (PC₆₁BM) which exposed that D-1 is the best choice for achieving higher PCE. TDM (transition density matrix), DOS (density of states) analysis, and binding energies all were estimated at MPW1PW91/6-31G (d, p) level of DFT (density functional theory). All the architecture molecules show reduced band gap and high electron transfer rate due to the lowest reorganization energy (RE) of electron. The results show that there is greater contribution of acceptor and conjugated donor core towards the total absorption into the visible region of the spectrum. When tailored molecules D-1, D-2, D-3, and D-4 were blended with fullerene derivative polymer (PC₆₁BM), they give high values of voltage at zero current level (V_oc) compared to R.

Theoretical design of D-π-A system new dyes candidate for DSSC application

Currently, dye-sensitized solar cells (DSSCs) are one of the energy technologies that has piqued the interest of researchers, due to their distinct characteristics such as excellent air stability, ease of synthesis and photovoltaic properties interesting. This work aims to study the optoelectronic properties and photovoltaic of six organic dyes based on phenothiazine (PTZ). The effects of bridging core modifications of recently synthesized PSB-4(R) molecule on structural, photovoltaic, electronic, and optical properties of D1-D6 are studied. Using the method Density Functional Theory (DFT) level of the B3LYP (Becke three-parameter Lee-Yang-Parr) exchange correlation functional with 6-31G (d, p) and time-dependent DFT (TD-DFT). According to the obtained results, optoelectronic properties and photovoltaic of the dyes, we can suggest that these designed molecules are better sensitizers as a candidate for the production of dye solar cells (DSSCs). This theoretical study paves the way for chemists to synthesize more efficient sensitizers for applications in dye solar cells.

Designing of benzodithiophene core-based small molecular acceptors for efficient non-fullerene organic solar cells

Nowadays, organic solar cells (OSCs) with non-fullerene electron acceptors provide the highest efficiencies among all studied OSCs. To further improve the efficiencies of fullerene-free organic solar cells, end-capped acceptor modification is made with strong electron withdrawing groups. In this report, we have theoretically designed five new novel Benzodithiophene core-based acceptor molecules (H1-H5) with the aim to study the possible enhancement in photophysical, optoelectronic, and photovoltaic properties of newly designed molecules. The end-capped acceptor modification of famous and recently synthesized FBDIC molecule has been made with strong electron withdrawing groups. Density functional theory and time-dependent-density functional theory are extensively used to study the structural-property relationship, optical properties and various geometrical parameters like frontier molecular orbitals alignment, excitation and binding energy, transition density matrix along with open circuit voltage, density of states and dipole moment. Commonly, low reorganization energies (hole and electron) afford high charge mobility and our all designed systems are enriched in aspect (λ_e = 0.0044-0.0104 eV and λ_h = 0.0060-0.0090 eV). Moreover, H1-H5 molecules demonstrate red-shifting in absorption spectrum (λ_max = 741-812 nm) as compare to R (λ_max = 728 nm). Low excitation and binding energies with low HOMO (highest occupied molecular orbital)-LUMO (lowest unoccupied molecular orbital) energy gap of H1-H5 suggested that designed molecules are better and suitable candidates for high performance organic solar cell. Results of all analysis indicate that this theoretical framework demonstrates that end-capped acceptors modification is a simple and effective alternative strategy to achieve the desirable optoelectronic properties. Therefore, H1-H5 are recommended to experimentalist for out-looking future developments of highly efficient solar cells.

End-capped group manipulation of non-fullerene acceptors for efficient organic photovoltaic solar cells: a DFT study

A series of acceptors, S1-S5, has been designed based on the acceptor-π-donor-π-acceptor (A-π-D-π-A) architecture by incorporating a phenothiazine unit as the central donor unit. Density functional theory (DFT) and time-dependent density functional theory (TD-DFT) methods have been employed to study the effect of various end-capped groups on the geometric, electronic, optical and charge transport properties of the designed acceptor molecules. The results reveal that on increasing the electron-withdrawing nature of the end-capped groups, the performance of the acceptor molecules increases. It is also observed that on increasing the flexibility of the end-capped groups, the planarity of the molecules gets destroyed and, as a result, the performance of the acceptor molecules decreases. The investigated molecules exhibit high electron affinity (EA) and low reorganization energy for electrons (λ-), indicating the electron acceptor nature of the designed molecules. The absorption properties of the molecules manifest that compounds S2-S4 possess high values of the maximum wavelength (λmax) of absorption. We have also studied the properties of a D/A active layer by considering PffBT4T-2OD as the electron donor and arranging PffBT4T-2OD/S1-S5 molecules in a face to face manner. Properties of the D/A blend indicate that molecules S2-S4 have capacity to promote charge carrier separation at the D/A active layer. Our results provide guidelines for further designing of acceptors to enhance the performance of organic solar cells (OSCs).

Designing Star-Shaped Subphthalocyanine-Based Acceptor Materials with Promising Photovoltaic Parameters for Non-fullerene Solar Cells

Star-shaped three-dimensional (3D) twisted configured acceptors are a type of nonfullerene acceptors (NFAs) which are getting considerable attention of chemists and physicists on account of their promising photovoltaic properties and manifestly promoted the rapid progress of organic solar cells (OSCs). This report describes the peripheral substitution of the recently reported highly efficient 3D star-shaped acceptor compound, STIC, containing a 2-(3-oxo-2,3-dihydroinden-1-ylidene)malononitrile (IC) end-capped group and a subphthalocyanine (SubPc) core unit. The 3D star-shaped SubPc-based NFA compound STIC is peripherally substituted with well-known end-capped groups, and six new molecules (S1-S6) are quantum chemically designed and explored using density functional theory (DFT) and time-dependent DFT (TDDFT). Density of states (DOS) analysis, frontier molecular orbital (FMO) analysis, reorganization energies of electrons and holes, open-circuit voltage, transition density matrix (TDM) surface, photophysical characteristics, and charge-transfer analysis of selected molecules (S1-S6) are evaluated with the synthesized reference STIC. The designed molecules are found in the ambience of 2.52-2.27 eV with a reduction in energy gap of up to 0.19 eV compared to R values. The designed molecules S3-S6 showed a red shift in the absorption spectrum in the visible region and broader shift in the range of 605.21-669.38 nm (gas) and 624.34-698.77 (chloroform) than the R phase values of 596.73 nm (gas) and 616.92 nm (chloroform). The open-circuit voltages are found with the values larger than R values in S3-S6 (1.71-1.90 V) and comparable to R in the S1 and S2 molecules. Among all investigated molecules, S5 due to the combination of extended conjugation and electron-withdrawing capability of end-capped acceptor moiety A5 is proven as the best candidate owing to promising photovoltaic properties including the lowest band gap (2.27 eV), smallest λe = 0.00232 eV and λh = 0.00483 eV, highest λmax values of 669.38 nm (in gas) and 698.77 nm (in chloroform), and highest V oc = 1.90 V with respect to HOMOPTB7-Th-LUMOacceptor. Our results suggest that the selected molecules are fine acceptor materials and can be used as electron and/or hole transport materials with excellent photovoltaic properties for OSCs.

Designing indenothiophene-based acceptor materials with efficient photovoltaic parameters for fullerene-free organic solar cells

Non-fullerene small molecular acceptors (NFSMAs) exhibit promising photovoltaic performance which promoted the rapid progress of organic solar cells (OSCs). In this study, an attempt is done to explore indenothiophene-based high-performance small molecular electron acceptors for organic solar cells. We have designed five acceptor molecules (M1-M5) with strong donor moiety indenothiophene linked to five different end-capped group acceptor moieties: diflouro-2-methylene-3-oxo-2,3-dihydroindene-1-ylidene)malononitrile (A1), 1-(dicyanomethylene)-2-methylene-3-oxo-2,3-dihydro-1H-indene-5,6-dicarbonitrile (A2), methyl-6-cyano-3-(dicyanomethylene)-2-methylene-1-oxo-2,3-dihydro-1H-indene-5-carboylate (A3), 2-(6-cyano-5-fluoro-2-methylene-3-oxo-2,3 dihydro-1H-indene-1-ylidene)malononitrile (A4), and (Z)-methyl 3-(benzo [c][1,2,5]thiadiazol-4-yl)-2-cyanoacrylate (A5) respectively. The structure-property relationship was studied and effects of structural modification on the optoelectronic properties of these acceptors (M1-M5) were determined systematically by comparing it with reference molecule R, which is recently reported as excellent non-fullerene-based small acceptor molecule. Among all designed molecules, M5 is proven as a suitable candidate for organic solar cell applications due to better photovoltaic properties including narrow HOMO-LUMO energy gap (2.11 eV), smallest electron mobility (λ_e = 0.0038 eV), highest λ_max values (702.82 nm in gas) and (663.09 nm in chloroform solvent) and highest open-circuit voltage (V_oc = 1.49 V) with respect to HOMO_PTB7-Th-LUMO_acceptor. Our results indicate that introducing more end-capped electron-accepting units is a simple and effective alternative strategy for the design of promising NFSMAs. This theoretical framework also proves that the conceptualized NFSMAs are superior and thus are recommended for the future construction of high-performance organic solar cell devices. Graphical abstract.

A DFT study to probe homo-conjugated norbornylogous bridged spacers in dye-sensitized solar cells: an approach to suppressing agglomeration of dye molecules

This work reports a sigma-bridged framework as spacers to design new dye-sensitized solar cells. The norbornylogous bridged spacer can avoid π–π aggregation of dye molecules on the semiconductor surface in DSSCs. These sesquinorbornatrienes are known to exhibit electron propagation through the interaction of sigma and π orbitals via through bond (OITB) and through space (OITS) mechanisms. Density functional theory (DFT) calculations performed with these spacers and a modelled simple donor unit like N,N-dimethylamine and cyanoacrylic acid as the anchoring group showed significant results with the requisite optical parameters for DSSCs. The newly designed dyes have shown comparable or better optical properties compared to the reference dye molecule with π-conjugated thiophene spacer units. The ΔG_injection, V_OC and μ_normal values calculated for the designed dyes were found to be higher than those of the reference system. The trans-sesquinorbornatriene system spacer (6-D) showed a V_OC of 3.3 eV, ΔG_injection of 2.4 eV and oscillatory strength (f) of 0.96. The total and partial density of states indicates a good communication between the valence and conduction band for the designed dyes. Transition density matrix results suggest that the exciton dissociation in the excited state is sufficiently high to overcome the coulombic attraction of the hole. These results are promising for the design of dye molecules with such scaffolds, to achieve better efficiency and to eliminate one of the major issues with π-spacer units in DSSCs.

This work reports homoconjugated norbornylogous spacers to supress agglomeration of dye molecules with improved efficiency of dye sensitized solar cells.

Designing dithienonaphthalene based acceptor materials with promising photovoltaic parameters for organic solar cells

Scientists are focusing on non-fullerene based acceptors due to their efficient photovoltaic properties. Here, we have designed four novel dithienonaphthalene based acceptors with better photovoltaic properties through structural modification of a well-known experimentally synthesized reference compound R. The newly designed molecules have a dithienonaphthalene core attached with different acceptors (end-capped). The acceptor moieties are 2-(5,6-difluoro-2-methylene-3-oxo-2,3-dihydroinden-1-ylidene)malononitrile (H1), 2-(5,6-dicyano-2-methylene-3-oxo-2,3-dihydroinden-1-ylidene)-malononitrile (H2), 2-(5-methylene-6-oxo-5,6-dihydrocylopenta[c]thiophe-4-ylidene)-malononitrile (H3) and 2-(3-(dicyanomethylene)-2,3-dihydroinden-1-yliden)malononitrile (H4). The photovoltaic parameters of the designed molecules are discussed in comparison with those of the reference R. All newly designed molecules show a reduced HOMO-LUMO energy gap (2.17 eV to 2.28 eV), compared to the reference R (2.31 eV). Charger transfer from donor to acceptor is confirmed by a frontier molecular orbital (FMO) diagram. All studied molecules show extensive absorption in the visible region and absorption maxima are red-shifted compared to R. All investigated molecules have lower excitation energies which reveal high charge transfer rates, as compared to R. To evaluate the open circuit voltage, the designed acceptor molecules are blended with a well-known donor PBDB-T. The molecule H3 has the highest V oc value (1.88 V). TDM has been performed to show the behaviour of electronic excitation processes and electron hole location between the donor and acceptor unit. The binding energies of all molecules are lower than that of R. The lowest is calculated for H3 (0.24 eV) which reflects the highest charge transfer. The reorganization energy value for both the electrons and holes of H2 is lower than R which is indicative of the highest charge transfer rate.

Designing triazatruxene-based donor materials with promising photovoltaic parameters for organic solar cells

To address the increasing demand of efficient photovoltaic compounds for modern hi-tech applications, efforts have been made herein to design and explore triazatruxene-based novel donor materials with greater efficiencies. Five new molecules, namely M1-M5, were designed by structural modification of acceptor moiety (rhodanine-3-acetic acid) of well known experimentally synthesized JY05 dye (reference R), and their optoelectronic properties are evaluated to be used as donor molecules in organic solar cells. In these molecules M1-M5, triazatruxene acts as a donor unit and benzene spaced different end-capped moieties including 2-(4-(dicyanomethylene)-2-thioxothiazolidin-3-yl)acetic acid (A1), (E)-2-(4-(1-cyano-2-methoxy-2-oxoethylidene)-2-thioxothiazolidin-3-yl)acetic acid (A2), (Z)-2-(3'-ethyl-4'-oxo-2,2'-dithioxo-3',4'-dihydro-2'H,5H-[4,5'-bithiazolylidene]-3(2H)-yl)acetic acid (A3), (Z)-2-(4'-(dicyano-methylene)-3'-ethyl-2,2'-dithioxo-3',4'-dihydro-2'H,5H-[4,5'-bithiazol-ylidene]-3(2H)-yl)acetic acid (A4) and 2-((4Z,4'E)-4'-(1-cyano-2-methoxy-2-oxoethylidene)-3'-ethyl-2,2'-dithioxo-3',4'-dihydro-2'H,5H-[4,5'-bithiazolylidene]-3(2H)-yl)acetic acid (A5) respectively, as acceptor units. The electronic, photophysical and photovoltaic properties of the designed molecules M1-M5 have been compared with reference molecule R. All designed molecules exhibit reduced energy gap in the region of 1.464-2.008 eV as compared to reference molecule (2.509 eV). Frontier molecular orbital (FMO) surfaces confirm the transfer of charge from donor to acceptor units. All designed molecules M1-M5 exhibited an absorption spectrum in the visible region and they were broader as compared to that of reference R. Especially, M5 with highest λ max value 649.26 nm and lowest transition energy value 1.90 eV was accredited to the strong electron withdrawing end-capped acceptor moiety A5. The highest value of open circuit voltage (V oc) 1.02 eV with respect to HOMOdonor-LUMOBTP-4Cl was shown by M5 among all investigated molecules which was 0.15 V larger than reference molecule R. The designed molecule M5 is proven to be the best candidate for both electron and hole transport mobilities due to its smallest λ e (0.0212 eV) and λ h (0.0062 eV) values among all studied molecules.