Synthesis And Characterization Of Spiro-type Hole Transporting Materials For Perovskite Solar Cells

Photovoltaic technology is an effective means to solve the increasingly serious energy and environmental problems.After several decades of development,in addition to traditional crystalline silicon cells,various types of new solar cells have emerged,including thin film solar cells,organic thin-film solar cells,dye-sensitized solar cells and perovskite solar cells.In particular,the perovskite solar cells(PSCs),in just a few years have achieved a power conversion efficiency(PCE)excedding 22%,being selected by Science as one of the "2013 top ten scientific breakthrough".For the construction of PSCs,hole transporting materials(HTMs)are essential for the hole extraction from the perovskite layer.Although PSCs can also be fabricated without a hole transporting layer(HTL),efficiency and stability of such devices are obviously lower than those with HTL.Therefore,the design and synthesis of new HTMs are particularly important for improving the performance of PSCs.Organic molecules are a widely used class of HTMs owing to the ease of synthesis,good film-forming property,high hole mobility,high thermal stability,designable and adjustable chemical structures,etc.Organic HTMs can be divided into three categories according to their molecular structures:linear,star-shaped,and spiro-type.In particular,the latter has unique spatial conformation and the ?-conjugated structure,endowing them excellent thermal stability and high hole-transporting ability.Based on the basic working principle of PSCs combining with the energy level match between perovskite and HTM,this thesis will design and synthesize several new spiro-like organic molecules and investigate their properties and potential as HTM for PSCs.The main contents include:(1)Two kinds of peripheral fragments based on carbazoleand diphenylamine were designed and synthesized from cheap and easily available raw materials.(2)Two novel spiro-type structures and carbazole-aniline fragments were designed and synthesized.And Three HTMs(Spiro-IF,Spiro-X1,Spiro-X2)which are similar to the structure of spiro-OMeTAD were synthesized and two carbazole-aniline derivatives(Ph-D1 and Ph-D2)were synthesized and characterized by NMR and MS.(3)The novel synthesized materials were used in the perovskite solar cell.Under the same conditions,the maximum power conversion efficiency is 18.29%of spiro-OMeTAD,18.46%of Spiro-IF,14.74%of Spiro-X1,17.04%of Spiro-X2,13.81%of Ph-D1 and 18.28%of Ph-D2 in PSCs.