TY - JOUR
T1 - A hole-transport material that also passivates perovskite surface defects for solar cells with improved efficiency and stability
AU - Zhao, By Xiaoming
AU - Yao, Chao
AU - Gu, Kaichen
AU - Liu, Tianran
AU - Xia, Yu
AU - Loo, Yueh Lin
N1 - Funding Information:
The authors thank Dr E. Tsai’s and Dr R. Li’s help with X-ray scattering measurements, which were conducted at the Center for Functional Nanomaterials (CFN) and the Complex Materials Scattering (CMS) beamline of the National Synchrotron Light Source II (NSLS-II), which both are U.S. DOE Office of Science Facilities, at Brookhaven National Laboratory under Contract No. DE-SC0012704. The authors acknowledge the use of Princeton’s Imaging and Analysis Center, which is partially supported by the Princeton Center for Complex Materials, a National Science Foundation (NSF)-MRSEC program (DMR-1420541). Y.-L. Loo acknowledges support from the National Science Foundation, under grants DMR-1420541 and CMMI-1824674, and the U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy (EERE) under Solar Energy Technologies Office (SETO) Agreement Number DE-EE0008560. C. Yao acknowledges the support from China Scholarship Council (CSC File No. 201806010248). K. G. and Y.-L. Loo acknowledge support from ExxonMobil through its membership in the Princeton E-filliates Partnership of the Andlinger Center for Energy and the Environment.
Publisher Copyright:
© The Royal Society of Chemistry.
PY - 2020/11
Y1 - 2020/11
N2 - While typical perovskite solar cells (PSCs) with doped Spiro-OMeTAD as a hole transport material (HTM) have shown rapid increase in their power-conversion efficiencies (PCEs), their poor stability remains a big concern as the dopants and additives used with Spiro-OMeTAD have a strong tendency to diffuse into and degrade the perovskite active layer under normal operating conditions. Aiming to push forward the development of PSCs, many dopant-free small-molecular HTMs have been reported based on energetic considerations for charge transfer and criteria for charge transport. However, the PCEs of the state-of-the-art PSCs with dopant-free small-molecular HTMs are still inferior to those using doped Spiro-OMeTAD, and little attention has been paid to the interactions between the HTM and perovskite absorber in PSCs. Here, we report a facile design concept to functionalize HTMs so that they can passivate perovskite surface defects and enable perovskite active layers with lower density of surface trap states and more efficient charge transfer to the hole transport layer. As a consequence, perovskite solar cells with a functionalized HTM exhibit a champion PCE of 22.4%, the highest value for PSCs using dopant-free small molecular HTMs to date, and substantively improved operational stability under continuous illumination. With a T80 of (1617 ± 7) h for encapsulated cells tested at 30 °C in air, the PSCs containing the functionalized HTM are among the most stable PSCs using dopant-free small-molecular HTMs. The effectiveness of our strategy is demonstrated in PSCs comprising both a state-of-the-art MA-free perovskite and MAPbI, a system having more surface defects, and implies the potential generality of our strategy for a broad class of perovskite systems, to further advance highly efficient and stable solar cells.
AB - While typical perovskite solar cells (PSCs) with doped Spiro-OMeTAD as a hole transport material (HTM) have shown rapid increase in their power-conversion efficiencies (PCEs), their poor stability remains a big concern as the dopants and additives used with Spiro-OMeTAD have a strong tendency to diffuse into and degrade the perovskite active layer under normal operating conditions. Aiming to push forward the development of PSCs, many dopant-free small-molecular HTMs have been reported based on energetic considerations for charge transfer and criteria for charge transport. However, the PCEs of the state-of-the-art PSCs with dopant-free small-molecular HTMs are still inferior to those using doped Spiro-OMeTAD, and little attention has been paid to the interactions between the HTM and perovskite absorber in PSCs. Here, we report a facile design concept to functionalize HTMs so that they can passivate perovskite surface defects and enable perovskite active layers with lower density of surface trap states and more efficient charge transfer to the hole transport layer. As a consequence, perovskite solar cells with a functionalized HTM exhibit a champion PCE of 22.4%, the highest value for PSCs using dopant-free small molecular HTMs to date, and substantively improved operational stability under continuous illumination. With a T80 of (1617 ± 7) h for encapsulated cells tested at 30 °C in air, the PSCs containing the functionalized HTM are among the most stable PSCs using dopant-free small-molecular HTMs. The effectiveness of our strategy is demonstrated in PSCs comprising both a state-of-the-art MA-free perovskite and MAPbI, a system having more surface defects, and implies the potential generality of our strategy for a broad class of perovskite systems, to further advance highly efficient and stable solar cells.
UR - http://www.scopus.com/inward/record.url?scp=85096524156&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85096524156&partnerID=8YFLogxK
U2 - 10.1039/d0ee01655a
DO - 10.1039/d0ee01655a
M3 - Article
AN - SCOPUS:85096524156
SN - 1754-5692
VL - 13
SP - 4334
EP - 4343
JO - Energy and Environmental Science
JF - Energy and Environmental Science
IS - 11
ER -