甲基胺處理鈣鈦礦薄膜的光物理和電性探討

Structural, Photophysical, and Electrical Properties of Methylamine-Treated Perovskite Thin Films

喬冠豪(Guan-Haw Chiao)

指導教授 ： 孫建文

國立交通大學/理學院/應用化學系所/碩士(2018年)

摘要

有機-無機混合鈣鈦礦 (organic-inorganic hybrid perovskite; OIHP) 擁有許多新穎的性質，除了應用於太陽能電池之吸光材料上，也成功的應用於光電元件上，例如發光二極體和雷射。高結晶度多晶鈣鈦礦薄膜製程之簡化對於光伏和光電元件性能發展是至關重要的，然而，目前對於晶體缺陷之影響知之甚少，多晶鈣鈦礦薄膜之不均勻性，仍需進一步改善。
在本文中，我們以甲基胺 (methylamine; MA) 蒸氣處理旋塗法製成之鈣鈦礦薄膜後，薄膜之品質在結構、外觀以及電性方面明顯改善，這些改變可能反映在光電元件之效率以及再現性之提升。XRD和SEM結果清楚的顯示，旋塗法製成之MAPbI3和MAPbBr3薄膜經過MA蒸氣處理後，均勻性、結晶大小以及結晶度明顯增加。
除了使用吸收光譜、穩態和時間解析螢光光譜，來探討MA蒸氣處理對鈣鈦礦薄膜吸收光、放射光、能隙和載子生命期之影響之外。我們也使用霍爾係數和電性量測，來研究載子濃度、遷移率、電阻率以及光導電度的改變。結果顯示MA蒸氣處理過之MAPbI3和MAPbBr3薄膜，其外觀和結晶性之變化，可以反映在載子遷移率、生命期和電性上。此外，經過MA蒸氣處理之薄膜能隙大小也因缺陷態之減少而略為藍移。

關鍵字

鈣鈦礦 ； 甲基胺

並列摘要

Organic-inorganic hybrid perovskites (OIHP) have many novel properties and have been applied to the light absorbing material of solar cells, as well as been successfully demonstrated in optoelectronics, such as light-emitting diodes and lasers. Easy fabrication of polycrystalline perovskite thin films with high crystallinity has been essential to the rapid advancement of the photovoltaic and optoelectronic performance. However, there still remain much demands for further improvement since there exists significant inhomogeneity in the polycrystalline films, and little is known about the defect physics.
Herein, we demonstrated that, with treatment of methylamine (MA) vapor to the spin-coated perovskite film, quality of the film was significantly improved structurally, topologically and electronically, which can possibly lead to more efficient and reproducible photovoltaic and optoelectronic devices. Our XRD and SEM results clearly indicated increase inthe homogeneity, grain size and crystallinity of the spin-coated MAPbI3 and MAPbBr3thin films after treated with the MA vapor.
The influence of MA vapor treatment in the emission, absorption, energy gap, and carrier lifetime were also investigated using the absorption, steady-state, and time-resolved photoluminescence spectroscopy. The carrier concentrations, mobility, electrical resistivity, and photoconductivity of the treated MAPbI3and MAPbBr3thin film were also studied using the Hall coefficient and current-voltage measurements. The improvement in morphology and crystallinity of theMA-treatedMAPbI3 and MAPbBr3 thin films was clearly reflected in the observed enhanced carrier mobility, lifetime, and electrical conductivity. The bandgaps of the MA-treated films were found slightly blue-shifted due to the reduced defect states in the band tail.

並列關鍵字

perovskite ； methylamine

參考文獻

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