Rational Molecular Design towards NIR Absorption; Efficient Diketopyrrolopyrrole Derivatives for Organic Solar Cells and Photothermal Therapy

After the development of diketopyrrolopyrrole (DPP) in 1974, its derivatives have been widely explored for optoelectronic applications. In this review we discussed various donor/acceptor functionalized DPPs which are recently published and systematically compared their properties among themselves along with literature. The modification of donor functionalized DPP to tetracyanobutadiene (TCBD) bridged derivatives with improved acceptor strength, absorption towards near infra-red region have shown some exciting advancement in non-fullerene acceptors for organic solar cells and as therapeutic agents in photodynamic therapy are also described. The optoelectronic properties in relation to structural changes such as change of end capping groups, donor–acceptor moieties, aromatic moiety in DPP core and number of DPP units in the molecular structure are discussed. We are expecting that the current review will provide guidelines for the exploration of new DPP based efficient materials for photovoltaic and biomedical applications.