Synthesis Of Small Molecular Based On IDT Derivatives And Their Application In Organic Solar Cells

In this paper, we have designed and synthesized a series of novel narrow band-gap organic small molecular materials and applied to organic solar cell, the main work contains two parts:In the first part, we design and synthesize a series of small molecular donor materials based on D1-A-D2-A-D1 linear frameworks. Silaindacenodithiophene-based molecular donor have an SIDT-based core as the central donor unit(D2), with two difluorobenzothiadiazole as the acceptor, and two n-hexyl-substituted bithiophene or two n-dodecyl-substituted bithiophene as the terminal groups(D1). Moreover, it was desirable to employ an extra selenophene π bridge unit to enhance the light-harvesting ability and employ an two n-hexyl-substituted bithiophene π-electron delocalization and solid-state intermolecular packing. In combination with using PC71 BM as the acceptor, the BHJ-OSC devices based on SIDTC6 exhibited PCE of 4.44 %, with a high open circuit voltage(Voc) of 0.85 V, short circuit current density(Jsc) of 9.55 m A cm-2 and high FF of 0.57 for the device without using any additives.In the second part, we have synthesized a series of A-D-A linear frameworks nonfullerene acceptors. The three non-fullerene acceptors consist of 2D-IDT, 2DNIDT and NIDT as the central donor unit(D), two perylene diimide(PDI) as the acceptor(A). We mainly investigate the influence of spacer units on molecular properties such as the thin film morphology, and charge carrier mobility in the device. As a result, the three moleculars exhibit different geometries. C ompared with IDTPDI, NIDTPDI exhibits a relatively planar structure. NIDT2C12 PDI has higher planarity and suffered from strong aggregation, which limited their performance in solution-processed bulk heterojunction(BHJ) OSCs. As a result, the BHJ-OSC devices based on NIDTPDI exhibited PCE of 2.1%, with short circuit current density(Jsc) of 6.88 mA cm-2 and high FF of 0.4, open circuit voltage(Voc) of 0.76 V for the device without using any additives.