Research On The Efficient Organic Tandem Solar Cells

Organic tandem solar cell(TOSC)broadens the absorption spectrum with the complementary current of front and rear cells,coming to front and showing a good prospect.But it still remains difficulties and challenges on its construction and preparation.Especially in two aspects,the one is the lower light field current attributed to the shared light absorption for the subcells,leading a low short-circuit current density(Jsc)which could be the minimum vaule of the subcells.The other is that the interconnection layer(ICL)requires a multiple performance,such as Solvent resistance,light transmittance,transmission rate,ohmic contact,etc.Therefore,we systematically analyzes and studies the spectrum broadening with current balance for subcells and the optimization for ICL,as follows.1.For active layers,we select the materials with complenmentary absorption to broden the spectral response,and obtain the balanced Jsc with the tertiary receptor admixture.We propose a universal method of solvent-flushing to building component distribution in photoactive layer based on the different solubility of the donor and acceptor in acetylacetone,and the power conversion effeciency(PCE)significantly increases to 16.51%based on PBDB-TF:Y6.In addition,for the better soulubility and faster evaporation,the chloroform is introduced for the solvent of rear active layer instead of chlorobenzene to build a better morphology.2.For ICL,we modify the surface free energy for frequently-used hole transport layer of PEDOT to prepare on the front cell.And we choose the TIPD form the electron transport layer of Zn(acac)2,Al(acac)3,AZO,TIPD,which are free from evaporation and synthesis process,to construct a high performance ICL of m-PEDOT/TIPD.After optimization and processing,we estabilsh an integrity TOSC with excellent property based on the ICL,and obtain the PCE of 15.26%.