Efficient Standalone Flexible Small Molecule Organic Solar Cell Devices: Structure-Performance Relation Among Tetracyanoquinodimethane Derivatives

Abstract

Currently, very few dicyano and tetracyanoquinodimethane (TCNQ) based molecules are utilized as active layers, sandwiched between the electron and hole transport layer in organic solar cell (OSC) devices. Nevertheless, simple mono-and disubstituted TCNQ derivatives as exclusively active layers are yet unexplored and provide scope for further investigation. In this study, TCNQ derivatives with varying amine substituents, namely, AEPYDQ (1), BMEDDQ (2), MATBTCNQ (3), and MITATCNQ (4), were explored as efficient standalone, flexible, all small molecule OSC devices. Particularly, 1 resulted in the highest device efficiency of 11.75% with an aromatic amine, while 2 possessing an aliphatic amine showed the lowest power conversion efficiency (PCE; 2.12%). Notably, the short circuit current density (J SC ) of device 1 increased from 2 mA/cm 2 in the dark to 9.12 mA/cm 2 under light, indicating a significant boost in the current generation. Further, 1 manifested more crystallinity than others. Interestingly, 4 exhibited a higher PCE (5.90%) than 3 (PCE is 2.58%), though 3 is disubstituted with an aromatic amine, probably attributed to the electron-withdrawing effects of the −CF 3 and −CN groups in 3 reducing the available π-electron density for stacking. Therefore, this study emphasizes crystallinity, significantly on the PCE, offering insights into the design of many such efficient OSCs.

Comprehensive Review on Downconversion/Downshifting Silicate-Based Phosphors for Solar Cell Applications

“…Solar energy offers a promising way forward, and India is significantly interested in this direction . Research is ongoing on next-generation solar cells that are fabricated using dye-sensitized colloidal TiO 2 , − silicon, − perovskite, − and organic-based materials. − From an industrial standpoint, however, silicon photovoltaics (PVs) continue to be the preferred option. In fact, they alone occupy about 90% of the PV market owing to silicon’s merits; viz., it is nontoxic, an ample element in the earth, an elemental semiconductor, and so on.…”