Department of Physics
The properties of the hole transporting layer (HTL) play an important role in determining the performance of the inverted planar perovskite solar cells (PSCs). High performing methylammonium lead iodide PSCs were demonstrated through controlled growth of the perovskite layer and suppression of charge recombination at the perovskite/electrode interfaces. In this work, the effect of sodium citrate modified poly (3,4-ethylenedioxythiophene): poly (4- styrenesulfonate) (PEDOT:PSS) HTL on the growth of the perovskite active layer, charge extraction properties and hence the performance of the PSCs was investigated. Power conversion efficiency (PCE) of >11.50% was achieved for low-processing temperature solution-processable PSCs made with a sodium citrate modified PEDOT:PSS HTL, which is >20% higher than that of a structurally identical control PSC with a pristine PEDOT:PSS HTL (9.13 %). Photoelectron spectroscopy measurements reveal that sodium citrate solution modification partially removes the PSS on surface of the PEDOT:PSS HTL, leading to almost two times increase in the ratio of PEDOT to PSS as compared to that measured for the pristine PEDOT:PSS HTL. Light intensity dependent J−V characteristics of the PSCs were carried out to analyze the performance enhancement of the PSCs. The results reveal that the sodium citrate modified PEDOT:PSS HTL benefits the efficient operation of PSCs in two ways: (1) it assists the crystal growth to increase in the perovskite domain size, and (2) it favors the charge collection in the PSCs.
Source Publication Title
Journal of Materials Chemistry C
Royal Society of Chemistry
Link to Publisher's Edition
Syed, A., Poon, C., Li, H., & Zhu, F. (2019). Sodium citrate modified-PEDOT:PSS hole transporting layer for performance enhancement of inverted planar perovskite solar cells. Journal of Materials Chemistry C, 7 (18), 5260-5266. https://doi.org/10.1039/C8TC06043F