Effect of dihydronaphthyl-based C60 bisadduct as third component materials on the photovoltaic performance and charge carrier recombination of binary PBDB-T : ITIC polymer solar cells

Durable polymer solar cells produced by the encapsulation of a WSe2 hole-transport layer and β-carotene as an active layer additive

WSe2 nanoflakes are obtained by liquid-phase exfoliation. Polymer solar cells with NF-WSe2 as the hole transport layer (HTL) are realized with superior photovoltaic characteristics.

A wrinkled structure with broadband and omnidirectional light-trapping abilities for improving the performance of organic solar cells with low defect density

Fabricating thin film solar cells on the light-trapping structures is an effective way to improve the absorption of the active layer. Here, we report a non-fullerene organic solar cell based on a PBDB-T:ITIC active layer, a wrinkled metal rear electrode, and a MoO3/Ag/ZnS front transparent electrode. Optical characterization shows that the wrinkled metal structure can remarkably increase the absorption of the active layer in a broadband range. The resulting device shows a power conversion efficiency of 8.2%, which increases by 4.6% compared to that of the flat counterpart. Apart from higher absorption, the improved performance can also be ascribed to the efficient charge transport and collection in the device due to the lower defect density, larger interfacial area, and smaller active layer thickness. A device with a power conversion efficiency of 10.19% based on the flat ITO/glass substrate is also achieved. Accordingly, a power conversion efficiency of about 10.66% is predicted under the condition where the wrinkled rear electrode and the ITO front electrode are employed. In addition, the power conversion efficiency of the wrinkled device could increase by about 50.48% compared to that of the flat device under an incident angle of 60 °C, illustrating that a better omnidirectional ability is achieved.

Improved efficiency and thermal stability of ternary all-small-molecule organic solar cells by NCBA as a third component material

In this work, organic solar cells (OSCs) were fabricated with a blend of PC₇₁BM and p-DTS-(FBTTh₂)₂ employed as a binary photoactive layer and with a dihydronaphthyl-based C60 bisadduct (NCBA) small-molecule acceptor used as a third component material. We demonstrate that the short-circuit current density (J_SC), open-circuit voltage (V_OC), fill factor (FF), power conversion efficiency (PCE), and thermal stability can all be enhanced simultaneously. In addition, the crystallinity can be finely optimized and the photon harvesting ability was enhanced for short-wavelength light by adjusting the NCBA doping ratio, leading to efficient exciton dissociation and charge-carrier transport. At the same time, the ternary photoactive layer, with a small amount of NCBA as a third component material, reduced monomolecular recombination and bimolecular recombination under open-circuit and short-circuit conditions, respectively. Such a ternary structure with NCBA as a third component material helped enhance the crystallinity and fix the surface morphology of the photoactive layer, thus reducing the decay ratio while increasing the thermal annealing treatment time. Consequently, the PCE reaches 9.1% for ternary OSCs with a 12 wt% NCBA doping ratio in a blended acceptor, with 87.2% of the initial PCE value maintained after 100 h of thermal annealing treatment at 90 °C, which is much higher than that obtained for the PCE of binary OSCs.