저온공정 ZnO 적용에 따른 역구조 고분자 태양전지 소자 성능 연구

Abstract

Recently, active research is being conducted on polymer solar cells to improve powerconversion efficiency by developing new device structures, synthesizing polymer materials, andapplying them to charge extraction layers. In this study, we analyzed the influence of ZnO onthe performance of solar cells by using various ZnO thin films (using the high and lowtemperature sol-gel processes and the nanoparticle process) as an electron extraction layer ininverted polymer solar cells based on PBDB-T:ITIC. The ZnO thin film was formed by thehigh-temperature (450°C) sol-gel process, which resulted in an increase in the sheet resistanceof the ITO electrode by five times. As a result, the power conversion efficiency of the polymersolar cells was low (4.12%). Conversely, in the nanoparticle process, butanol-based ZnOexhibited better dispersion and surface properties than the IPA-based ZnO, resulting inimproved performance of the polymer solar cell (PCE of 6.35% and 4.58% with butanol andIPA-based ZnO, respectively). Additionally, a ZnO precursor solution was developed using thelow-temperature (150°C) sol-gel process, which was applied as an electron extraction layer inan inverted polymer solar cell. Consequently, the device performance significantly improved(PCE of 8.89%)due to the formation of a ripple-shaped surface, which facilitated the extractionof electrons due to the excellent surface roughness.