本研究利用量子理論計算與分析有機-無機混合鈣鈦礦太陽能材料（organic-inorganic hybrid perovskite）的光電轉換極限效率。鈣鈦礦是近年備受矚目的綠能材料，可做太陽能電池光吸收層，除便宜外其他優點極多，例如：光學吸收係數高、載子等效質量低、載子擴散長度增大、載子遷移率高、功率轉換效率可能增高、製作簡易及成本低廉...等特點。
本研究先以CH3NH3PbI3（亦即MAPbI3）鈣鈦礦作為基線材料，予以更改分子結構，嘗試改良性質。研究利用第一原理（First Principles）密度泛函理論（Density Functional Theory, DFT）模擬計算四方晶與立方晶型鈣鈦礦半導體礦石材料，建立單位晶胞模型後，再以平面波基底、Kohn-Sham定理、廣義梯度近似法（GGA）、交換相關勢能PBE以及自洽場（SCF）方法進行幾何結構最佳化。並透過電子能帶結構圖及電子態密度圖分析固態材料的能隙及光學性質，包含材料的複數相對介電常數、複數折射率、消光係數、反射率及吸收係數...等光學性質。
本研究進一步利用激發態熱力學觀點，計算MAPbI3的熵損失能量、焓、內能、化學勢能及光電轉換理論極限效率。研究中發現隨著溫度上升，熵損失的能量越多導致光電轉換效率降低，當溫度上升至300K每對電子電洞有0.27221 eV熵損失，其功率轉換效率剩下29.5％。第三部分本研究探討ABX3鈣鈦礦組成對能隙及吸收光譜之影響，十二種四方晶鈣鈦礦包含MAPbI3、MAPbCl3、MAPbBr3、MASnI3、MASnCl3、MASnBr3、FAPbI3、FAPbCl3、FAPbBr3、FASnI3、FASnCl3及FASnBr3，從中發現立方晶MAPbI3較四方晶MAPbI3呈微藍位移、有機陽離子（A=MA/FA），FABX3較MABX3呈微紅位移、金屬陽離子（B= Pb2+/Sn2+），ASnX3較APbX3呈微紅位移，以及鹵素陰離子（X=Cl/Br/I）隨著電負度增加（Cl＞Br＞I）呈顯著藍位移。故經適當調整能隙，鈣鈦礦亦可作為顯示器新型材料。

This thesis employed theoretical quantum mechanics to analyze photoelectric properties of organic-inorganic hybrid perovskite materials, which have attracted much attention on the photovoltaic (PV) devices in recent years. This is due to their exceptional advantages such as high optical absorption coefficient, low carrier masses, long diffusion length, high carrier mobility, maybe higher power conversion efficiency, and finally process simplicity and low fabrication cost.
The first part of this research employs the first-principles calculations to investigate the properties of the tetragonal and cubic structured MAPbI3 (CH3NH3PbI3) perovskites. Kohn-Sham density functional theory (DFT), exchange correlation functional (by Perdew et al), and plane wave basis with self-consistent field method were all employed. Solid state optical properties such as complex relative dielectric constant, complex refractive index, extinction coefficient, reflectivity, and absorption coefficient are presented.
The second part of this research adopted thermodynamics perceptions to evaluate the entropic loss energy, the enthalpy, internal energy and the chemical potential of the MAPbI3. Raising temperature will cause entropy more loss and decrease the power conversion efficiency (PCE). When temperature reaches 300K, the entropic loss of the electron-hole pair is 0.27221 eV, and the PCE lowers to 29.5％. Finally, the third part of this research varies the composition of the ABX3 into MAPbI3, MAPbCl3, MAPbBr3, MASnI3, MASnCl3, MASnBr3, FAPbI3, FAPbCl3, FAPbBr3, FASnI3, FASnCl3 and FASnBr3. Bandgaps were calculated and found that by proper trimming of the composition, the hybrid organic-inorganic perovskite materials can also be a potential display material in the near future.

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