全無機二維層狀錫鹵素鈣鈦礦奈米晶體
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2020
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近幾年來，由於鉛具有劇毒且環境危害，使無鉛的新型全無機鈣鈦礦材料變成研究的熱點，其中，以全無機錫鹵素鈣鈦礦為較具有前瞻性的替代品，因為具有較窄的能隙以及與鉛類似的光電特性。然而，三維錫鹵素鈣鈦礦在空氣中的穩定性極差，阻礙了三維錫鹵素鈣鈦礦在光伏領域上的發展，為了得到穩定性較佳且導電度較好的錫鹵素鈣鈦礦奈米材料，本篇研究使用熱注射法將十八烷二酸(Octadecanedioic acid)引入形成強的表面配體，成功合成出層數為三且相穩定的全無機二維層狀Ruddlesden-Popper (RP)相鈣鈦礦Cs4Sn3Br10奈米晶體。由電子顯微鏡觀察到材料大小約為150 nm的長方體，且選區繞射圖譜可對應X-光粉末繞射圖的繞射峰。由X-光粉末繞射圖中的重複單元確認該材料為層狀結構，其結果符屬於n = 3的計算圖。而其最大放光波長在450 nm，且螢光量子產率為12%。此外，由於量子井效應影響，使其放光波長產生藍移，並使螢光量子產率提升。另外，在室溫和相對濕度為60％的情況下通過固態螢光光譜儀和X-光繞射測量，發現二維材料的穩定性比三維材料更好。
Recently, many literatures demonstrated three-dimensional (3D) lead–free perovskite materials such as Tin-based all-inorganic perovskite CsSnX3 (X =Cl, Br, I) to replace toxic Pb-based all-inorganic perovskite. This class of materials have a narrow energy bandgap and the optical and electrical characteristics are similar to lead-based perovskite. However, the key issue for commercialization is poor environmental stability. In order to obtain perovskite nanomaterials with better stability, we present a strong binding energy surface ligand octadecanedioic acid (ODA) to synthesis all-inorganic Ruddlesden-Popper phase tin-based perovskite nanocrystals with a quantum well structure by hot injection method. The TEM images show a 150 nm rectangle and the SAED match with XRD patterns. The repeating unit of the XRD pattern confirms that the material is a layered structure, and the results are fitted the calculation pattern which belong to n=3. The PL emission of 3D CsSnBr3 is about 680nm, and the PLQY is below 1%. In contrast, the PL emission of 2D NCs is about 450 nm, and the PLQY is about 12%. As a result of strong quantum well effect, the PL emission blue shifted and the PLQY increased. Compared to 3D CsSnBr3 NCs (several hours), the 2D NCs performed better stability (one month) than 3D at room temperature under 60% relative humidity by solid-state PL and XRD measurement.
Recently, many literatures demonstrated three-dimensional (3D) lead–free perovskite materials such as Tin-based all-inorganic perovskite CsSnX3 (X =Cl, Br, I) to replace toxic Pb-based all-inorganic perovskite. This class of materials have a narrow energy bandgap and the optical and electrical characteristics are similar to lead-based perovskite. However, the key issue for commercialization is poor environmental stability. In order to obtain perovskite nanomaterials with better stability, we present a strong binding energy surface ligand octadecanedioic acid (ODA) to synthesis all-inorganic Ruddlesden-Popper phase tin-based perovskite nanocrystals with a quantum well structure by hot injection method. The TEM images show a 150 nm rectangle and the SAED match with XRD patterns. The repeating unit of the XRD pattern confirms that the material is a layered structure, and the results are fitted the calculation pattern which belong to n=3. The PL emission of 3D CsSnBr3 is about 680nm, and the PLQY is below 1%. In contrast, the PL emission of 2D NCs is about 450 nm, and the PLQY is about 12%. As a result of strong quantum well effect, the PL emission blue shifted and the PLQY increased. Compared to 3D CsSnBr3 NCs (several hours), the 2D NCs performed better stability (one month) than 3D at room temperature under 60% relative humidity by solid-state PL and XRD measurement.
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無鉛, 錫鈣鈦礦, 全無機, Ruddlesden-Popper, 奈米材料, Lead-free, Tin-based perovskite, all-inorganic, Ruddlesden-Popper, nanocrystal