(181m) Tuning the PEDOT Lattice Parameter By Engineering Dopant Level for Efficient and Stable Perovskite Solar Cell Device

Meysam Heydari Gharahcheshmeh¹, Mohammad Mahdi Tavakoli², Jing Kong², and Karen K. Gleason¹

¹Department of Chemical Engineering, ²Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, United States

Abstract

Conducting Polymers (CPs) are desired for next-generation flexible, stretchable, wearable, and large-area electronic devices. Electronic conductivity, optical transparency, and mechanical flexibility are a few of the many desirable properties achievable using CPs. The quality and tunable nature of vapor phase polymerization by oxidative chemical vapor deposition (oCVD) through engineering the dopant level bring the extraordinary advantage to control the crystalline orientation and lattice parameter in CPs. Here, we introduce an effective dopant control strategy using volatile liquid oxidant, vanadium oxytrichloride (VOCl₃), to systematically tune the structural, electrical, and optical properties of poly(3,4-ethylenedioxythiophene) (PEDOT) by the oCVD method. The stability improvement of perovskite solar cell (PSC) devices is a critical factor that needs to be considered for commercialization of these optoelectronic devices. A commonly used hole transport layer (HTL) in PSC device is PEDOT:poly(styrenesulfonate) (PEDOT:PSS). However, the high acidic nature of PEDOT:PSS solution restricts the stability and performance of optoelectronic devices. Here, we demonstrated the highly stable and efficient inverted PSC device based on oCVD PEDOT as an HTL. The PSC device based on oCVD PEDOT exhibited a higher power conversion efficiency (PCE) of 18.04% compared to its counterpart device based on spin-cast PEDOT:PSS (16.20%). In addition, the PSC device based on oCVD PEDOT displays approximately two-fold long-term stability compared to its counterpart device based on the PEDOT:PSS.

Keywords: oCVD, Conducting Polymers, PEDOT, perovskite solar cell

This work was supported by Eni S.p.A. under the Eni-MIT Alliance Solar Frontiers Program.

[1] M. Heydari Gharahcheshmeh, K. Gleason. Advanced Materials Interfaces. 6, 1801564 (2019).