Organic inorganic perovskite solar cells have seen tremendous developments in recent years. As a hole transport material, 2,2',7,7'-tetrakis(N,N-di-p-methoxyphenylamine)-9,9'-spirobifluorene (Spiro-OMe-TAD) is widely used in n-i-p perovskite solar cells. However, it may lead to the perovskite film degradation due to the dopant lithium bis-((trifluoromethyl)sulfonyl)amide (Li-TFSI), which has strong hydrophilicity. Cu9S5 is considered as a superior p-type transport material, which also has a favorable energy level matching with the highest occupied molecular orbital of Spiro-OMeTAD. Herein, a solution-processed organic-inorganic-integrated hole transport layer was reported, which is composed of the undoped Spiro-OMeTAD and Cu9S5 layer. Since there is no Li-TFSI doping, it is extremely conductive to the long-term stability of the solar cells. In the meantime, we proposed a method to adjust the lowest unoccupied molecular orbital (LUMO) of SnO2 via nitrogen implantation (N:SnO2). The LUMO of SnO2 can be tuned from -4.33 to -3.91 eV, which matches well with the LUMO of CH3NH3PbI3 (-3.90 eV), and thus helps to reduce hysteresis. The modified hole and electron transport layers were applied in n-i-p perovskite solar cells, which achieve a maximum power conversion efficiency (PCE) of 17.10 and 96% retention of PCE after 1200 h in air atmosphere without any encapsulation.

The electron-transporting material (ETM) is one of the key factors to determine the efficiency and stability of organic light-emitting diodes (OLEDs). A novel ETM with a ``(Acceptor)(n)-Donor-(Acceptor)(n)'' (''(A)(n)-D-(A)(n)'') structure, 2,7-di([2,2:6,2-terpyridin]-4-yl)-9,9-spirobifluorene (27-TPSF), is synthesized by combining electron-withdrawing terpyridine (TPY) moieties and rigid twisted spirobifluorene, in which the TPY moieties facilitate electron transport and injection while the spirobifluorene moiety ensures high triplet energy (T-1 = 2.5 eV) as well as enhances glass transition temperature (T-g = 195 degrees C) for better stability. By using tris[2-(p-tolyl)pyridine]iridium(III) (Ir(mppy)(3)) as the emitter, the 27-TPSF-based device exhibits a maximum external quantum efficiency (eta(ext, max)) of 24.5%, and a half-life (T-50) of 121, 6804, and 382 636 h at an initial luminance of 10 000, 1000, and 100 cd m(-2), respectively, which are much better than the commercialized ETM of 9,10-bis(6-phenylpyridin-3-yl)anthracene (DPPyA). Furthermore, a higher efficiency, a eta(ext, max) of 28.2% and a maximum power efficiency (eta(PE), (max)) of 129.3 lm W-1, can be achieved by adopting bis(2- phenylpyridine)iridium(III)(2,2,6,6-tetramethylheptane-3,5-diketonate) (Ir(ppy)(2)tmd) as the emitter and 27-TPSF as the ETM. These results indicate that the derivative of TPY to form (A)(n)-D-(A)(n) structure is a promising way to design an ETM with good comprehensive properties for OLEDs.

Two novel small molecules DTRDTQX and DTIDTQX, based on ditolylaminothienyl group as donor moiety and quinoxaline as middle acceptor moiety with different terminal acceptor groups were synthesized and characterized in this work. In order to study the photovoltaic properties of DTRDTQX and DTIDTQX, bulk-heterojunction solar cells with the configuration of FTO/c-TiO2/DTRDTQX(or DTIDTQX):C-70/MoO3/Ag were fabricated, in which DTRDTQX and DTIDTQX acted as the donors and neat C-70 as the acceptor. When the weight ratio of DTRDTQX :C-70 reached 1:2 and the active layer was annealed at 100 degrees C, the optimal device was realized with the power conversion efficiency (PCE) of 1.44%. As to DTIDTQX :C-70-based devices, the highest PCE of 1.70% was achieved with the optimal blend ratio ( DTIDTQX :C-70 = 1:2) and 100 degrees C thermal annealing treatment. All the experimental data indicated that DTRDTQX and DTIDTQX could be employed as potential donor candidates for organic solar cell applications.