Browsing by Author "Huang, Wenchao"

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High-Efficiency Organic Tandem Solar Cells With Effective Transition Metal Chelates Interconnecting Layer
(2017-10-01)
Chang, Sheng-Yung
;
Lin, Yu-Che
;
Sun, Pengyu
;
Hsieh, Yao-Tsung
;
Meng, Lei
Organic tandem solar cells have two sub-cells vertically connected via a tunnel junction (or interconnecting layer, ICL), which the ICL plays a critical role of determining the performance of the tandem cell. In this manuscript, we report a new design of the ICL consisting of zirconium (IV) acetylacetonate (Zr-Acac) as the electron transport layer. The Zr-Acac has a suitable work function to pin the Fermi-level of the ICL and hence, can effectively behave as the charge recombination function for the tandem device. Comparing to the reference device consisting of ZnO ETL layer, the Zr-Acac ICL can effectively enhance the efficiency by 20%, from 8.4 to 10.1% power conversion efficiencies. More importantly, the Zr-Acac ETL layer functions effectively without thermal annealing, which not only simplifies the tandem solar cell processing, but also widens the front sub-cell material selection.
Rational Tuning of Molecular Interaction and Energy Level Alignment Enables High-Performance Organic Photovoltaics
(1970-01-01)
Wang, Rui
;
Yuan, Jun
;
Han, Guangchao
;
Huang, Tianyi
;
Huang, Wenchao
The performance of organic photovoltaics (OPVs) has rapidly improved over the past years. Recent work in material design has primarily focused on developing near-infrared nonfullerene acceptors with broadening absorption that pair with commercialized donor polymers; in the meanwhile, the influence of the morphology of the blend film and the energy level alignment on the efficiency of charge separation needs to be synthetically considered. Herein, the selection rule of the donor/acceptor blend is demonstrated by rationally considering the molecular interaction and energy level alignment, and highly efficient OPV devices using both-fluorinated or both-nonfluorinated donor/acceptor blends are realized. With the enlarged absorption, ideal morphology, and efficient charge transfer, the devices based on the PBDB-T-F/Y1-4F blend and PBDB-T-F/Y6 exhibit champion power conversion efficiencies as high as 14.8% and 15.9%, respectively.