Record High Efficiency Achievement under LED Light in Low Bandgap Donor-Based Organic Solar Cell through Optimal Design

Abstract

Recently, a low bandgap donor named poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b ′ ]dithiophene-2,6-diyl-alt-(4-(2-ethylhexyl)-3-fluorothieno[3,4b]thiophene-)-2-carboxylate-2-6-diyl)]- (PTB7-Th-) based organic photovoltaic (OPV) devices has exhibited interesting behavior when tested under indoor light. Theoretically, a PTB7-Th : [6,6]-phenyl-C71-butyric acid methyl ester (PC70BM) active layer-based OPV can show >23% power conversion efficiency (PCE) under light-emitting diode (LED) light. However, to date, the experimentally achieved PCE (~11.63%) is significantly lower than the theoretical one. Therefore, we design an indoor OPV having PTB7-Th : PC70BM active layer and low-acidic and cheaper polypyrrole : polystyrene sulfonate (PPY : PSS) as the hole transport layer (HTL), by optimizing active layer thickness and processing conditions (spin coating speed and doping concentration) of the HTL via optical simulations and experiments. The results show that the device having 100 nm thick active layer and a PPY : PSS-based HTL (PPY : PSS; weight ratio between PPY and PSS 1 : 2) coated at 5000 rpm can exhibit a record high PCE value (16.35%) during its operation under 1000 lx LED lamp. In comparison, a commercially available PEDOT : PSS-based OPV can achieve maximum 14.21% PCE under the same conditions.

Advances in organic photovoltaic cells: a comprehensive review of materials, technologies, and performance

“…In the tandem PV cell, each sub-cell is comprised of an absorber material and an electron transport material. 122,125 The absorber material is responsible for absorbing the incoming photons and generating electron-hole pairs (excitons), while the electron transport material facilitates the separation and transport of the generated charge carriers.…”

Recent developments in non-fullerene-acceptor-based indoor organic solar cells

“…In IOSCs, interfacial materials facilitate the extraction and transport of photo-generated charges, such as electrons and holes, from the active layer to the appropriate electrodes [51]. Efficient charge extraction is crucial to minimize losses and ensure high device performance [52]. Interfacial layers, such as ETLs and HTLs, are typically utilized to enhance charge extraction by aligning energy levels and providing suitable pathways for charge transport [50,52].…”

“…Efficient charge extraction is crucial to minimize losses and ensure high device performance [52]. Interfacial layers, such as ETLs and HTLs, are typically utilized to enhance charge extraction by aligning energy levels and providing suitable pathways for charge transport [50,52]. In IOSCs, unintended charge recombination at the interfaces can cause large efficiency losses.…”

Smart indoor organic photovoltaic cells for controlling health monitoring sensors: harnessing sustainable energy solutions for efficient sensing systems

“…In [22], poly (3,4ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS): CuNW-based transparent composite electrodes have shown to offer a viable alternative to conventional materials, addressing issues related to cost, flexibility, and performance. The findings have paved the way for the realization of scalable and efficient indoor energy harvesting techniques, thereby advancing the applicability of OPVs in the diverse environments [23]. Traditional batteries face limitations in terms of size, weight, and environmental impact, prompting the exploration of alternative energy-harvesting technologies.…”