Defect-Stabilized Tin-Based Perovskite Solar Cells Enabled by Multi-Functional Molecular Additives

When and Where

Nov 30, 2022
8:00pm - 10:00pm

Hynes, Level 1, Hall A

Presenter

Jinhyeok Choi

Seok Joo Yang

Kilwon Cho

Co-Author(s)

Jinhyeok Choi¹,Seok Joo Yang¹,Kilwon Cho¹

Pohang University of Science and Technology¹

Abstract

Jinhyeok Choi¹,Seok Joo Yang¹,Kilwon Cho¹

Pohang University of Science and Technology¹

Lead-based perovskite solar cells (Pb-PSCs) with efficiency over 25% and high stability have been reported, however, the toxicity of Pb turns into main hurdle for commercialization of PSCs due to the environmental hazards. Tin-based perovskite solar cells (Sn-PSCs) are most viable candidates for replacing the Pb owing to the high carrier mobility, small exciton binding energy, and narrow optical bandgap. However, facile oxidation of Sn2+ and high defect density on surfaces and grain boundaries in Sn-PSCs complicate the task of obtaining highly stable Sn-PSCs. Here, for the first time, a fulleropyrrolidine with a triethylene glycol monoethyl ether side chain (PTEG-1) is introduced as a multi-functional molecular additive to passivate both surfaces and grain boundaries of formamidnium (FA)-based tin triiodide (FASnI3) perovskites. The ether group and fullerene group in PTEG-1 interact with Sn2+ and I–, respectively, and thereby inhibit formation of Sn4+ and I3–, which is detrimental to the stability of Sn-PSCs. We observed that this multi-functional molecular additive suppresses non-radiative recombination and increases both power conversion efficiencies (PCEs) and the stability of Sn-PSCs. As a result, Sn-PSCs with PTEG-1 additives exhibited PCEs of 7.40 %, which is accompanied by retaining 65 % of its initial PCE of encapsulated PSCs after 1000 h of exposure to ambient air with light illumination. Our results would provide a guideline for future design of multi-functional molecules with suitable functional groups to fabricate highly stable Sn-PSCs.