Researchers from the University of Surrey in the United Kingdom have fabricated an inverted perovskite solar cell by using a surface modulator that reportedly facilitates superior passivation on perovskite surfaces, increasing overall cell efficiency. As the surface modulator, the scientists tested two organic halide salts known as 4-hydroxyphenethylammonium iodide (HO-PEAI), and 2-thiopheneethylammonium iodide (2-TEAI).
“These modulators can affect the surface energy of the perovskite films,” they explained.
They noted that the two compounds can dramatically reduce non-radiative interfacial recombination. This can have a significant impact on electrical performance in perovskite cells, with implications for open-circuit voltage, short-circuit current, fill factor, and ultimately, power conversion efficiency. They reported that “2-TEAI showed a stronger interaction than HO-PEAI, forming a quasi-2D structure on the perovskite surface without further annealing.”
The scientists built the p-i-n structured cell with poly-TPD coated indium tin oxide (ITO) substrate, a hole transport layer made of carbazole (2PACz), the perovskite layer, the 2-TEAI modulator, an electron acceptor made of phenyl-C61-butyric acid methyl ester (PCBM), a bathocuproine (BCP) buffer layer, and a silver (Ag) metal contact. The salts were deposited onto the surface of perovskite films through a facile spin-coating process without annealing.
Through different measurements, the research team ascertained that the surface modulator does not alter the absorption spectra of perovskite films.
“The 2-TEAI induces a deeper valence band edge, which is expected to provide a stronger hole-blocking effect at the perovskite/PCBM interface and thus is more beneficial for reducing the interfacial recombination,” the group said. “Based on these results, we believe the 2-TEAI would enhance the open-circuit voltage of manufactured perovskite solar cells.”
The solar cell achieved a power conversion efficiency of 21.85%, which the scientists described as the highest reported efficiency for inverted perovskite solar cells that use 2PACz as the hole transport layer. The device also achieved an open-circuit voltage of 1.2 V, a short-circuit current of 21.93 mA cm−2, and a fill factor of 0.83. For comparison, a reference perovskite solar cell without the modulator achieved an efficiency of 19.95 and was able to retain only 53% of the initial efficiency after 180 minutes.
“The findings suggest that the role of the modulator is more than surface passivation,” the scientists concluded. “Our study will provide insight into the selection and molecular design of post-treatment materials for highly efficient and stable perovskite solar cells.”
They described the cell design in “Suppressing Interfacial Recombination with a Strong-Interaction Surface Modulator for Efficient Inverted Perovskite Solar Cells,” which was recently published in Advanced Energy Materials.
This content is protected by copyright and may not be reused. If you want to cooperate with us and would like to reuse some of our content, please contact: editors@pv-magazine.com.
4 comments
By submitting this form you agree to pv magazine using your data for the purposes of publishing your comment.
Your personal data will only be disclosed or otherwise transmitted to third parties for the purposes of spam filtering or if this is necessary for technical maintenance of the website. Any other transfer to third parties will not take place unless this is justified on the basis of applicable data protection regulations or if pv magazine is legally obliged to do so.
You may revoke this consent at any time with effect for the future, in which case your personal data will be deleted immediately. Otherwise, your data will be deleted if pv magazine has processed your request or the purpose of data storage is fulfilled.
Further information on data privacy can be found in our Data Protection Policy.