A novel small-molecule BODIPY-acceptor was synthesized by extending the BODIPY- diketopyrrolopyrrole excited electron delocalization through the BODIPY meso-carbon, the ideal position for BODIPY's excited electron delocalization. This BODIPY acceptor shows unprecedented broad and intense absorption (see the figure), having a dual role as the wide and narrow band gap organic acceptor.

Solution processed titanium (diisopropoxide) bis(2,4-pentanedionate) (TIPD) is utilized as both electrode modification layer and intermediate layer for inverted homo tandem polymer solar cells with a best V_oc of 1.54 V which is almost two times that of the single BHJ-PSC (0.78 V), and an enhanced PCE up to 8.11% has been achieved.

A new nonfullerene acceptor, ITIC-OEG was synthesized by replacing the normal alkyl substituents with OEG side-chains and the dielectric constant was greatly enhanced. The incompatibility between PPDT2FBT and ITIC-OEG (due to high hydrophilic nature of OEG chains) resulted in poor blend morphology, showing inefficient charge separation and significant charge recombination with small J_SC and PCE.

All-polymer blend employing fluorinated polymer PT-BT2F exhibits more efficient charge transfer between donor and acceptor compared to that employing non-fluorinated PT-BT/N2200 blend. As a result, all-PSCs unitizing PT-BT2F as donor and N2200 as acceptor output higher PCE than PT-BT/N2200 based device.

A case study addressing the effect of fusing indaceno[2,1-b:6,5-b’]dithiophene (IDT) core by incorporating separated benzene rings on the photovoltaic performance of designed molecular acceptor, is demonstrated.

With P3HT as donor, three spirofluorene-benzotriazole based non-fullerene small molecule acceptors display largely different photovoltaic performances strongly depending on the subtituted terminal acceptor units.

A novel n-type conjugated polymer based on dicyanodistyrylbenzene and naphthalene diimide units for all-PSCs could achieve an enhanced PCE of 4.26%.

A new kind of polymer electron acceptors based on fluorinated isoindigo (F-IID) as the electron- deficient building block has been developed. The resulting polymers based on F-IID show low-lying LUMO/HOMO energy levels, high electron mobilities and broad absorption spectra, enabling applications as electron acceptors in polymer solar cells.

How the conjugated polymers affect the crystallization of DR3TBDTT, in addition to the corresponding morphology and performance, is not well understood. We introduced PTB7-Th, PCDTBT and P3HT to investigate the influence of crystallization. We found that despite of energy level alignment, the crystallization of DR3TBDTT influenced by polymers determines the corresponding morphology of active layers and photovoltaic performance.

Non-fullerene acceptors show much larger and uneven ESP distributions than fullerene acceptors, which should play a crucial role in affecting the charge generation in OSCs.

Silaindacenodithiophene (SiIDT), a Si-bridged fused ring, is introduced to construct a new narrow band gap non-fullerene acceptor. Its polymer solar cells combining a well-known PBDB-T donor can show a power conversion efficiency up to 8.16%.

Four copolymers based on DPP and carbazole with tetrathiophene porphyrin (TTP) side chains linked by a flexible alkyl-interval were synthesized for polymer solar cells. The results showed that XP11 with the ratio (2/8) of TTP/DPP possesses the best PCE of 5.11%.