Light Management Engineering And Preparation Methods For High-stability Semi-transparent All-polymer Solar Cells

With the development of modern society,environmental problems become more serious.Photovoltaic technology,which directly converts solar energy into electric energy,promotes the development of solar energy application.Polymer solar cells(PSCs)show tremendous research interests because of their distinct merits in solution processibility,flexibility and semi-transparency.Recently,the semi-transparent PSCs have attracted extensive attention as a prospect that can be applied in the field of the building photovoltaic integration.However,semi-transparent PSCs still face the great challenges in achieving high power conversion efficiencies(PCEs),stability and outstanding light transmittance.Therefore,the main work of this dissertation is to select excellent polymer donors well matched with the advanced polymer acceptor,and to fabricate semi-transparent all-polymer solar cells(all-PSCs)with different device architectures,so as to explore the relationship among PCEs,transmittance and stability detailedly.(1)Two polymer donors(PBDB-T and PCE-10),matched with polymer acceptor(N2200),were utilized to prepare the conventional semi-transparent all-PSCs.By changing the thickness of different electrodes and the thickness of active layers,the photovoltaic performance was explored in two different active layer systems,respectively.Furthermore,the photovoltaic performance,light transmittance and stability of PBDB-T:N2200 and PCE-10:N2200 based semi-transparent all-PSCs were compared in detail.(2)PBDB-T:N2200 based semi-transparent all-PSCs show the optimal efficiency of 7.07%,and an average transmittance of 44.78% in visible light region.Through the test on thermal stability,it can maintain the initial efficiency of about 80% after 1200 hours in a nitrogen glove box,indicating that the semi-transparent devices exist the good photovoltaic performance and stability.The best efficiency of the semi-transparent all-PSCs based on PCE-10:N2200 is 6.03%,and the average transmittance in the visible region is 58.71%.It still keeps about 80% of the initial efficiency after 1100 hours in the nitrogen glove box.Furthermore,the photovoltaic performance,light transmittance and stability of these two systems are compared in detail.In addition,the PCE-10:N2200 system is also selected to further explore the photovoltaic performance in the inverted and flexible semi-transparent all-PSCs via the advanced device optimization.(3)The PCEs and transmittance of inverted semi-transparent all-PSCs prepared by PCE-10:N2200 system are lower than those of the devices within conventional device structure.The efficiency is only 5.01%,and the visible light transmittance is 43.17%,respectively.However,the stability of inverted semi-transparent device is more excellent,and the inverted semi-transparent device with silver electrode thickness of 50 nm can keep 80% of initial efficiency after 1300 hours in nitrogen glove box.In this dissertation,the study on flexible semi-transparent all-PSCs shows that its photovoltaic performance is not so good,and the development of flexible devices still face great challenges.(4)This work investigates the effects of silver electrodes with different thicknesses on the PCEs,transmittance and stability of the semi-transparent all-PSCs.As the electrode thickness is decreases,the PCE and device stability are decreased,whereas the transmittance is increased.The AVT effect of semi-transparent all-PSCs with different electrode thicknesses is almost opposite to the influence on device performance.