Benzothiadiazole Based Cascade Material to Boost the Performance of Inverted Ternary Organic Solar Cells

Abstract

A conjugated, ladder-type multi-fused ring 4,7-dithienbenzothiadiazole:thiophene derivative, named as compound ‘T’, was for the first time incorporated, within the PTB7:PC71BM photoactive layer for inverted ternary organic solar cells (TOSCs) realization. The effective energy level offset caused by compound T between the polymeric donor and fullerene acceptor materials, as well as its resulting potential as electron cascade material contribute to an enhanced exciton dissociation, electron transfer facilitator and thus improved overall photovoltaic performance. The engineering optimization of the inverted TOSC, ITO/PFN/PTB7:Compound T(5% v/v):PC71BM/MoO3/Al, resulted in an overall power conversion efficiency (PCE) of 8.34%, with a short-circuit current density (Jsc) of 16.75 mA cm−2, open-circuit voltage (Voc) of 0.74 V and a fill factor (FF) of 68.1%, under AM1.5G illumination. This photovoltaic performance was improved by approximately 12% with respect to the control binary device.

Novel Materials for Semi-Transparent Organic Solar Cells

“…These include benzo [1,2-b:4,5-b ′ ]dithiophene (BDT) [44], carbazole [45], thiophene [46,47], and benzo [1,2-b:4,5-b ′ ]difuran [48,49]. As for the A units, the most frequently employed materials are benzothiadiazole [50][51][52], benzotriazole [53], and benzodithiophene-4,8-dione (BDD) [54]. Researchers have experimented with several structural modifications to enhance the photovoltaic performance of these copolymers.…”

Conducting Nanofibers: Diagonal Scrolling of 2D Nanosheets into 1D Nanostructures via In Situ Self-Assembly

“…In this report, we chose benzothiadiazole (BTD) as an electron acceptor for the design of P2 to achieve extended absorption in the NIR region, enhanced photostability, and electrical conductivity. BTD is well known for its excellent electron-transporting ability due to the electron-withdrawing imine “N” atoms that enable lowering of lowest unoccupied molecular orbital (LUMO) energy levels. , Thus, the presence of porphyrin and benzothiadiazole in P2 signifies excellent electron donor and acceptor abilities that facilitate efficient electron transfer, while aggregation improves electrical conductivity. Detailed photophysical and microscopic studies imply that P2 exhibits aggregation in cyclohexane that leads to hierarchical growth of 2D and 1D self-assembled nanostructures via scrolling mechanism (Figure ).…”

Advanced Progress of Organic Photovoltaics

“…This Special Issue on "Advanced progress of organic photovoltaics" includes nine papers from different groups,which refer to the theoretical research for excitons generation, charge separation and recombination of OPVs [1], the innovation of active layer materials [2][3][4] and interfacial layer materials [5], the optimization of photoelectric conversion process based on a ternary strategy [6], the investigation of encapsulation technology [7], the reviews related to film-forming kinetic process of OPVs [8], and high efficiency OPVs with PCE over 17% [9].…”

“…From the device engineering perspective, ternary OPVs have been established to improve photon harvesting of active layers as much as possible by integrating two acceptors/one donor or two donors/one acceptor with complementary absorption spectra into one active layer. In Miron Krassas et al [6] a conjugated and ladder-type multi-fused ring 4,7-dithienbenzothiadiazole:thiophene derivative (compound 'T') was synthesized and incorporated into PTB7:PC 71 BM host system to construct ternary OPVs. The incorporation of the compound T led to a favorable energy cascade between PTB7 and PC 71 BM, which should be beneficial to charge transfer.…”