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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 37: Poster Session III
CPP 37.10: Poster
Wednesday, April 3, 2019, 11:00–13:00, Poster B1
Comparative study of interface modification and passivation approaches on low-temperature SnO2 and their effect on perovskite solar cell performance — •Max Grischek, Philipp Tockhorn, Ganna Chistiakova, Lukas Kegelmann, and Steve Albrecht — Helmholtz-Zentrum Berlin, Berlin, 12489, Germany.
SnO2 is a widely used electron transporting material (ETM) in planar n-i-p-type perovskite solar cells (PSC). It allows high Voc above 1.15 V and efficiencies close to 21%. In addition, low process temperatures make SnO2 a suitable ETM for flexible foils or monolithic silicon-perovskite tandem solar cells. However, high device efficiencies require thorough optimization of the SnO2 surface. This study investigates modification and passivation approaches on SnO2 and compares their effect on chemical composition, energetics, charge carrier extraction, interface recombination and performance in PSCs. Firstly, a dipole interlayer between SnO2 and the absorber is utilized to reduce the SnO2 workfunction and its conduction band offset to the absorber, as implied by UPS. This is shown to reduce interface recombination losses and increase the device Voc, as revealed by absolute PL and J-V measurements. Similar effects are observed when introducing very thin interlayers of PCBM/PMMA mixtures. The best PSC performance is achieved by an O2-plasma treatment of the SnO2 surface. Using J-V, TRPL and absolute PL measurements, less non-radiative recombination and faster charge carrier extraction are observed. This plasma treatment leads to reduced hysteresis and an enhancement in device efficiency to 18.1%.