Dual-Band, Efficient Self-Powered Organic Photodetectors with Isotype Subphthalocyanine-Based Heterojunctions toward Secure Optical Communications

High-performance heterojunction organic photodetectors (OPDs) are of great significance in optical detecting technology due to their tailorable optoelectronic properties. Herein, we designed and synthesized three n-type subphthalocyanine (SubPc) derivatives PhO-BSubPcF₁₂, CHO-PhO-BSubPcF₁₂, and NO₂-PhO-BSubPcF₁₂ via axial nonhalogen substitution on fluorinated SubPc. These SubPc derivatives exhibit improved intramolecular charge transfer, high electron mobilities, optimized energy levels, and good thermal stability. The novel isotype p-n SubPc heterojunctions are evaluated as photosensitive layers in OPDs, which show a UV-visible dual-band response and self-powered effect. The optimal OPD with Br-BSubPc/NO₂-PhO-BSubPcF₁₂ presents stable and superior performances with a high responsivity (R) of 0.14 A W^-1, a peak external quantum efficiency (EQE) of 30.6%, and an extremely low dark current of 0.92 nA cm^-2 under a 570-595 nm illumination without a bias voltage. It has outperformed most of the reported SubPc-based OPDs. The better interfacial contact of p-n SubPc derivatives leads to a large depletion region with decreased trap densities as well as a low carrier recombination rate, which is conducive to the photoinduced carriers' separation and well-balanced transport, resulting in high device performances. Moreover, a secure communication strategy is successfully demonstrated by dual-band optimal OPD. This work is expected to provide some guidance for molecular engineering and device performance toward multifunctional electronics.

Recent advances in subphthalocyanines and related subporphyrinoids

Subporphyrinoids constitute a class of extremely versatile and attractive compounds. Herein, a comprehensive review of the most recent advances in the fundamentals and applications of these cone-shaped aromatic macrocycles is presented.

Photoactive layers for photovoltaics based on near-infrared absorbing aryl-substituted naphthalocyanine complexes: preparation and investigation of properties

Photoactive layers based on substituted naphthalocyanines and conductive polymer MEH-PPV were prepared using the spin-coating technique and their conductivity was tested in dark and under illumination.

Reproduction of the UV-vis spectra of boron subphthalocyanine chloride in different solvents using time-dependent generalized Kohn–Sham density functionals with first solvation shell

Because of the unique physical, chemical and optical characteristics of boron subphthalocyanine chloride, it has been widely applied in different research fields and attracted global researchers. Deep insight into its UV-vis spectrum is required to understand the mechanism of the photon absorption of boron subphthalocyanine chloride in its condensed phase. In the present work, we utilize generalized Kohn–Sham density functionals with a non-equilibrium solvation model to simulate the UV-vis spectra of boron subphthalocyanine chloride in different solvents. Without considering the first solvation shell, we find that the slopes of lines drawn with [Formula: see text]B97XD and CAM-B3LYP results vs. experimental absorption wavelengths are close to 1.0 and root–mean–square deviations are less than 40 nm. We also find that the inclusion of the first solvation shell surrounding boron subphthalocyanine chloride monomers generally makes the calculated results worse. Finally, we discover that the simulated results overestimate oscillator strength of electronic absorption spectra in the ultraviolet region with respect to experimental spectra. These results imply that it may be important to consider the aggregation of solute molecules in order to understand the electronic absorption spectra of subPC in solution