PQT, PBTTT, PDQT and PDBT-co-TT were used to replace spiro-OMeTAD as efficient hole transporting layers in perovskite solar cells.

To investigate the influences of the 5,6-difluoro-benzoselenadiazole: 5,6-difluoro-benzothiadiazole (FBSe:FBT) ratio to the polymer properties, solid-state morphology and device performances, a series of FBSe:FBT based copolymers were synthesized. Copolymers with higher FBSe ratios were found to have narrower E g , and higher-lying E HOMO . Because of the size and electronegativity differences of the selenium and sulfur atoms, the FBSe:FBT ratio further affects the structural regularity of the conjugated chains, and their self-assembly behaviors. DSC results indicated that P1, which has the most irregular FBSe:FBT sequence along the backbone showed the lowest T m . Interestingly, XRD results showed that the main-chain irregularity degrades the order of the lamellar stacking, but not the order of π-stacking. The random ternary copolymers, P1 and P2, possess more ordered π-stacking than the alternating copolymers, PTh 4 FBSe and PTh 4 FBT. The highest OFET µ h of 0.46 cm 2 V -1 s -1 was delivered by P1, which has the smallest d π-π among the copolymers. In the polymer:PC 71 BM blend films, the FBSe containing copolymers have good miscibility to PC 71 BM. The degree of phase separation of PTh 4 FBSe:PC 71 BM can be enhanced by DIO additive, but it is not effective for the random ternary copolymers. Highest PCE of 6.06% with V oc of 0.64 V, J sc of 15.3 mA/cm 2 , and FF of 61.8% were delivered by the PTh 4 FBSe:PC 71 BM PSCs.

The first demonstration on the bendable substrateless GaN LED on a-SiC buffer transferring to the dielectric and metallic substrates.