Long-term stable polymer solar cells with significantly reduced burn-in loss

Abstract

The inferior long-term stability of polymer-based solar cells needs to be overcome for their commercialization to be viable. In particular, an abrupt decrease in performance during initial device operation, the so-called 'burn-in' loss, has been a major contributor to the short lifetime of polymer solar cells, fundamentally impeding polymer-based photovoltaic technology. In this study, we demonstrate polymer solar cells with significantly improved lifetime, in which an initial burn-in loss is substantially reduced. By isolating trap-embedded components from pristine photoactive polymers based on the unimodality of molecular weight distributions, we are able to selectively extract a trap-free, high-molecular-weight component. The resulting polymer component exhibits enhanced power conversion efficiency and longterm stability without abrupt initial burn-in degradation. Our discovery suggests a promising possibility for commercial viability of polymer-based photovoltaics towards real solar cell applications.

UV-Induced Oxygen Removal for Photostable, High-Efficiency PTB7-Th:PC71BM Photovoltaic Cells

“…The UV light at wavelengths below 400 nm was filtered out using a GG400 filter in order to reduce the undesirable photochemical reactions and burn-in loss [37][38] . An in-depth study on the burn-in degradation dynamics for PTB7-Th: PC 71 BM based inverted cells will be published elsewhere.…”

Stability of graphene-based heterojunction solar cells

“…Kong et al 157 pointed to burn-in loss, leading to degradation, as one of the main factors in the short life span of polymer-based solar cells. The initial burn-in loss was decreased by separating pristine photoactive polymers and trap-embedded components using the molecular weight distributions, which resulted in enhanced PCE and longterm stability of polymer solar cells without sudden initial burnin degradation.…”

Stability enhancement of normal-geometry organic solar cells in a highly damp condition: A study on the effect of top electrodes

“…MoO x was chosen for the anodic buffer layer instead of poly(3,4-ethylene dioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) given that it reportedly shows better endurance against moisture [14]. A blend of poly[N-9 00 -hepta-decanyl-2,7-carbazole-alt-5,5-(4 0 ,7 0 -di-2-thien yl-2 0 ,1 0 ,3 0 -benzothiadiazole)] (PCDTBT) (1-Material, Inc.) and [6,6]-phenyl C70-butyric acid methyl ester (PCBM70) (Nano-C, Inc.) was used for the active layer, which showed no particular degradation in its bulk even after direct exposure to a moist condition [12]. The normal cells were kept in an environmental chamber (TH-PE-025, JEIO Tech) which was pre-set to a damp condition, with a temperature of 27°C and a relative humidity of 90%, the condition close to ISOS-D-3 [15].…”

“…Numerous factors (e.g. heat, light, moisture) and their combinations can influence the integrity of OSCs, which makes analysis of OSC stability a complicated matter and calls for systematic studies under a controlled ambient [6][7][8]. Not only the organic active layers but also the electrode/interfacial buffer layers were found to be weak links with regard to device stability under an ambient environment.…”