| 摘要: | 近年來鈣鈦礦太陽能電池(Perovskite solar cells，簡稱PSCs)，由於組裝過程簡易且原料成本低而快速發展。而常見高效率之PSCs之電洞傳遞層(hole transporting layer, HTL)材料為Spiro-OMe-TAD，但其電洞遷移率低，因此科學家持續投入開發作為PSC HTM之高電洞遷移率的高分子。本研究是以先前本實驗室所開發的P15的結構為基礎以具有高平面性及剛性結構BDT(benzodithiophene)衍生物為Donor，以具有拉電子能力好的PQ(pyrido-quinoxaline)衍生物為Acceptor。接續在Acceptor上引入triethylene glucol monomethyl ether單元(TEG)增加高分子的溶解度，合成出高分子P19，並將P15、P19的π-bridge以selenophene取代thiophene，合成出高分子P17、P20，接著再將P15、P17、P20中Donor的側鏈上引入Cl原子，合成出高分子P16、P18、P21，以此探討7個高分子的性質及作為PSC之HTL時的光伏表現。高分子熱裂解溫度約落在261 oC ~ 348 oC，且水接觸角皆大於90o具有疏水性。高分子膜的UV-Vis吸收光譜顯示各個高分子的最大吸收波長落在610到660 nm之間，且π-bridge為selenophene的P17、P18、P20、及P21的最大吸收波長比π-bridge為thiophene的P15、P16、及P19紅位移。在Donor的側鏈上引入氯原子的高分子P16、P18、及P21之HOMO能階較沒引入氯原子的P15、P17、P19、及P20之HOMO能階低。將高分子作為PSC之電洞傳遞層所組裝之PSC元件，光電轉換效率以π-bridge為selenophene的P17 (7.33%)、及P18 (10.21%)比π-bridg為thiophene的P16 (6.28%)、及P19 (0.02%)好。然而高分子P15為HTL所組裝之PSC元件效率(15.56%)比P16、P17、及P18為HTL所組裝之元件效率高，因P15分子量最大使其膜面最平坦且緻密。但以含有TEG取代基的P19、P20、及P21為HTM的PSC元件之光電轉換效率都不高，可能是此三個高分子無法由旋轉塗佈法在鈣鈦礦膜上製備一個完整且連續的膜，因此電洞無法順利傳遞到電極。其中以P15為HTM所組裝之PSC元件有最高的光電轉換效率，為15.56%。;Perovskite solar cells (PSCs) have developed rapidly due to the simple assembly process and low raw material costs. The commonly used hole transporting material (HTM) with high-efficiency PSCs is spiro-OMe-TAD, but its hole mobility is low. Therefore, the development of polymers with high hole mobility as the hole transporting materials (HTMs) is an important research. This study is to develop D-A polymeric HTMs for PSCs. P15, which is previously prepared in our laboratory, having BDT (benzodithiophene) derivative (with high planarity and rigid structure) as the donor unit and PQ (pyrido-quinoxaline) derivative (with good electron withdrawing ability) as the acceptor unit was used as a model polymer. Triethylene glucol monomethyl ether (TEG) unit was used as a substitute to increase the solubility to form polymer P19. Thiophene in P15 and P19 was replaced with selenophene as the π-bridge to obtain polymer P17 and P20. Chlorine atoms were introduced into the side chains of the donor (to increase the interaction between polymer chains) in P15, P17, and P20 to synthesize P16, P18, and P21. The thermal stability of the polymers are about 261 oC ~ 348 oC. The water contact angle of all polymer films is greater than 90o, which means they are all hydrophobic. UV-Vis absorption spectra show that the λmax of the six polymers falls between 608 and 654 nm, and the λmax values of P17, P18, P20, and P21, which has selenophene bridge are longer than those of P15, P16, P19 where the π-bridge is thiophene. The HOMO energy levels of P16, P18, and P21 having chlorine atoms in the side chain are lower than those of P15, P17, P19, and P20 without chlorine atoms. PSC devices based on P17, P18, P20, and P21 (with π-bridge of selenophene) HTLs have higher efficiency than those of P16 and P19 (with thiophene π-bridg) as HTLs. However, the photoelectric efficiency of the PSC device assembled by the polymer P15 (15.56%) with HTL is higher than that of the device assembled by the P16, P17, and P18 as the HTL. Because the molecular weight of P15 is the largest, the film surface is the most flat and dense. The efficiencies of PSCs based on P19, P20, and P21 HTMs are very low. It is due to the three polymers cannot form a continuous film on top of perovskite by spin coating method. |
