Journal
ACS APPLIED MATERIALS & INTERFACES
Volume -, Issue -, Pages -Publisher
AMER CHEMICAL SOC
DOI: 10.1021/acsami.2c10928
Keywords
wide-bandgap perovskite; perovskite solar cells; surface modification; interfacial energy barrier; nonradiative recombination; low photovoltage loss
Funding
- National Key Research and Development Program of China [2021YFB3800100, 2021YFB3800101]
- National Natural Science Foundation of China [62004089, U19A2089]
- Guangdong Basic and Applied Basic Research Foundation [2022A1515011218, 2019B1515120083]
- Shenzhen Science and Technology Program [JCYJ 2 0 1 9 0 8 0 9 1 5 0 8 1 1 5 0 4, JCYJ20200109141014474]
- Shenzhen Engineering Re-search and Development Center for Flexible Solar Cells
- Shenzhen Development and Reform Committee [2019-126]
- Innovation and Entrepreneurship Training program for College students [S202014325010]
- Guangdong-Hong Kong-Macao Joint Laboratory [2019B121205001]
- General Research Fund [HKBU 12304320]
- Initiation Grant for Faculty Niche Research Areas (IG-FNRA) [(2020/21) -RC-FNRA-IG/20-21/SCI/06]
- Special Zone Support Program for Outstanding Talents of Henan University [CX3050A0970530]
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This study proposes a bifunctional modification approach to optimize wide-bandgap perovskite surfaces by adding an ultrathin layer of PEAAc, which simultaneously reduces surface defects and mitigates interfacial energy barriers, thereby improving the performance of perovskite devices.
Wide-bandgap perovskites as a class of promising top-cell materials have shown great promise in constructing efficient perovskite-based tandem solar cells, but their intrinsic relatively low radiative efficiency results in a large open-circuit voltage (VOC) deficit and thereby limits the whole device performance. Reducing film flaws or optimizing interfacial energy level alignments in wide-bandgap perovskite devices can efficiently inhibit nonradiative recombination to boost device VOC and efficiency. However, the simultaneous regulation on both sides and their underlying mechanism are less explored. Herein, a bifunctional modification approach is proposed to optimize the wide-bandgap perovskite surface with an ultrathin layer of phenylethylammonium acetate (PEAAc) to synchronously decrease the surface imperfection and mitigate the interfacial energy barrier. This treatment effectively heals under-coordinated surface defects through the formation of chemical interaction between the perovskite and PEAAc, bringing about a much slower charge trapping process and dramatically decreasing nonradiative recombination losses. Meanwhile, the passivation-induced upshifted Fermi level of the perovskite contributes to accelerated electron extraction and larger Fermi-level splitting under illumination. Consequently, the PEAAc-modified wide-bandgap (1.68 eV) device achieves an optimal efficiency of 20.66% with a high VOC of 1.25 V, among the highest reported VOC values for wide-bandgap perovskite devices, enormously outperforming that (18.86% and 1.18 V) of the device without passivation. In addition, the radiative limit of VOC for both cells is determined to be 1.42 V, delivering nonradiative recombination losses of 0.24 and 0.17 V for the control and PEAAc-modified devices, respectively. These results highlight the significance of the bifunctional modification strategy in achieving high-performance wide-bandgap perovskite devices.
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