Affiliation:
1. Department of Chemical Engineering National Taiwan University Taipei 10617 Taiwan
2. Center for Condensed Matter Sciences National Taiwan University Taipei 10617 Taiwan
3. Department of Chemical and Materials Engineering Southern Taiwan University of Science and Technology Tainan 71005 Taiwan
4. Department of Vehicle Engineering National Taipei University of Technology Taipei 10608 Taiwan
5. Department of Molecular Science and Engineering National Taipei University of Technology Taipei 10608 Taiwan
6. Center of Atomic Initiative for New Materials National Taiwan University Taipei 10617 Taiwan
Abstract
The introduction of additives with specific functional groups is an important approach to extend the operational lifetime of perovskite solar cells (PSCs). Herein, the effect of the additives of benzoic acid (0F‐B), 4‐fluorobenzoic acid (1F‐B), and 2,3,4,5,6‐pentafluorobenzoic acid (5F‐B) on the performance and stability of MAPbI3‐based PSCs is systematically investigated. These additives can both chelate onto lead ions and form hydrogen bond with methyl ammonium ions. These combined interactions result in an increased activation energy for nucleation of perovskite crystals, thereby, increasing crystal size, reducing defect formation, improving electronic properties, as well as reducing ion migration. As a result, PSCs added with 5F‐B achieve the highest power conversion efficiency (PCE) of 20.50% with a narrow distribution compared to those PSC devices added with 1F‐B (19.25 %), 0F‐B (18.80 %), and pristine devices (18.53 %). Notably, 5F‐B‐added PSCs retain 80% of their initial PCE after ≈100‐day humidity test (at 25 °C and 50% relative humidity), 30‐day thermal stability test (at 85 °C in nitrogen environment), and 12‐day light illumination test (under continuous simulated solar radiation).
Funder
National Science and Technology Council
Academia Sinica
National Taiwan University