使用全新二維銨鹽之二維混三維無鉛鈣鈦礦太陽能電池

Abstract

鈣鈦礦太陽能電池商業化最大的問題點，即是高效率的電池元件都需要使用毒性極高的鉛鈣鈦礦。相對於此，錫鈣鈦礦有相對低的毒性並且其能隙以太陽能電池吸光層而言幾乎理想，是目前最有機會替代鉛鈣鈦礦的材料。但不幸的是，除了效率上不及鉛鈣鈦礦以外，錫鈣鈦礦更有嚴重的穩定性問題。 為了解決這些問題，我們使用全新的二維銨鹽製備混合二維結構與三維結構之錫鈣鈦礦電池。由我們的分析結果發現，這樣的結構組成有非常多的優勢，除了能提升薄膜品質，亦能提升載子生命週期以及降低陷阱密度。另外我們也發現混入低能隙的三維鈣鈦礦反而會讓元件電壓上升的有趣現象。經過這些調整後，我們成功地製備出非常穩定且高效率的元件。此元件相比純三維或甚至是純二維錫鈣鈦礦元件，都有更好的表現。此報告不僅呈現了一個表現較好的全新二維錫鈣鈦，更展現了以二維結構為主體之二維三維混和結構系統的潛力。

Toxicity of Pb used in high performance devices is the biggest hurdle for commercialization of perovskite solar cells (PSCs). Sn perovskite, which has low toxicity and nearly ideal band gap, is the most hopeful substitute for Pb perovskite. But unfortunately, Sn PSCs suffers from underwhelming efficiency and severe stability issue. To solve these problems, we utilized a brand new 2D component (TEA) to fabricate 2D mix 3D composition Sn perovskite solar cell. From our results, we realized these compositions have many beneficial effects, such as better film quality, better carrier lifetime, lower trap density to solar cell performance and stability. We also found out that mixing the lower band gap 3D perovskite to 2D perovskite surprisingly would yield higher Voc. After these arrangements, we were able to make Sn perovskite solar cell with good efficiency, and much better stability compared to conventional 3D Sn perovskite solar cell or even pure 2D Sn perovskite. The report not only demonstrate a new type of 2D Sn perovskite that has better performance, but also shows the potential of 2D dominant 2D mix 3D composition.