Theoretical Study of P-Type Dye Sensitized Solar Cell Materials

[[abstract]]在常見的有機染料中，通常都會以立體障礙較大的三苯胺(Triphenylamine)為推電子基團，但在P型染劑上，常用的P1染劑中卻發現三苯胺在分子軌域能階中電子分佈不均，因此可能會造成染敏電池效率的降低；故本篇藉由理論計算的方法，以密度泛函理論(DFT)與時間相關密度泛函理論(TDDFT)的電腦計算方式，來探討一系列染料有機分子結構在分子能階的電子分佈與光學性質，設計出一系列的染料分子結構，來減少這些缺失的產生，並藉此提高有機太陽能電池的效率。 而設計分子理念的方法，主要是以立體障礙較大的拉電子基團，如Borondipyrromethene(BODIPY)、Bis(fluoromesityl)boryl ((FMes)2B)、Bis(mesityl)boryl((Mes)2B)等有機棚化物為主，搭配噻吩當推電子基與dithieno [3,2-b:2’,3’-d] pyrroles (DTPs)當π橋，藉由添加額外一拉電子基團，將分子長度延伸，達到分子能階軌域的電子分離，設計出較適合當P型太陽能染敏電池的染料分子。 由本篇的論文的結果，可知以Bis(fluoromesityl)boryl((FMes) 2B)當拉電子基時，搭配Benzothiadizole (BTD)這組額外拉電子基團，其紅移的現象會至562 nm產生，並會使能隙變小。[[abstract]]In organic dye sensitizer, the donor part is use triphenylamine constantly, because of its steric effect. However in P-type organic sensitizer P1 still have some problem with its frontier molecular orbital electron population thus it may caused the dye-sensitized solar cell efficiency be lower. Therefore we use theoretical method by density functional theory (DFT) and time-dependent density functional theory (TDDFT) to facilitate us to design efficient sensitizers. Through these computational method can help us to simulate its uv-vis spectrum and molecular energy level value. Hence we can figure out which sensitizer it’s good for p-type dye-sensitized solar cell then enhance the solar cell efficiency. In order to design a good efficient sensitizers for P-type dye-sensitized solar cell, we use a series of Organoboron group, such as Borondipyrro-methene(BODIPY)、Bis(fluoromesityl)boryl((FMes)2B)、Bis(mesityl)boryl ((Mes)2B) in support of its steric effect and strong pull electron strength, with small donor part and dithieno [3,2-b:2’,3’-d] pyrroles (DTPs) for π bridge. As we add another different acceptor group to elongation our molecular than it may separate frontier molecular orbital electron population. Our results indicated when we use bis (fluoromesityl) boryl ((FMes) 2B) for acceptor group, and add another group help electron to inject to acceptor group more easily. It will be red shift to 562 nm and the energy gap will be decrease.[[note]]碩