We have developed an ITO/ZnO/CdSe/CdTe:CdSe/CdTe/Au novel device architecture based on solution processed CdTe and CdSe nanocrystals (NCs). The introduced hybrid CdTe:CdSe layer was made by mixing different NCs in solution, which allowed for tailoring the optoelectronic properties of the nanocomposite materials. Our novel devices demonstrated more than 30% improvement in Jsc compared with their bilayer analogue, resulting from suppressed recombination. The champion device showed a 6.25% PCE, which is a record for solution processed CdTe:CdSe p–n junction solar cells with the inverted structure. Most important of all, the devices showed extreme stability after storage for three days when maintained under ambient conditions, and less than 3% degradation was observed in PCE after 50 days of storage.

CdTe/CdSe nanocrystal (NC) solar cells with an inverted structure (ITO/ZnO/CdSe/CdTe/Au) have been successfully fabricated by a simple solution process coupled with layer-by-layer sintering techniques. It was found that the device performance is strongly dependent on the annealing strategy, the thickness of the acceptor layer and on the buffer layer of ZnO when the optimal thickness of CdTe is adopted. Without the ZnO buffer layer, a thin film of the CdSe NCs on an ITO substrate shows a rougher morphology, resulting in device shunting. However, when a 40 nm-thick ZnO buffer layer and 60 nm-thick CdSe were employed, the device shows a much higher PCE of 5.81% under device conditions, post-annealing at 340 °C. This value is the highest efficiency ever reported to date for a CdTe/CdSe NC solar cell. Comparing with CdTe/CdSe NC solar cells with the normal device configuration, this device with an inverted structure simultaneously offers good Ohmic contact for carrier collection and efficient harvesting of solar photons in a wide wavelength.

We developed novel hybrid ligands to passivate PbS colloidal quantum dots (CQDs), and two kinds of solar cells based on as-synthesized CQDs were fabricated to verify the passivation effects of the ligands. It was found that the ligands strongly affected the optical and electrical properties of CQDs, and the performances of solar cells were enhanced strongly. The optimized hybrid ligands, oleic amine/octyl-phosphine acid/CdCl2 improved power conversion efficiency (PCE) to much higher of 3.72 % for Schottky diode cell and 5.04 % for p–n junction cell. These results may be beneficial to design passivation strategy for low-cost and high-performance CQDs solar cells.

We report the synthesis of CdTe semiconductor nanocrystals (NCs) with multi-armed, rod and tetrapod shapes, developed by a facile solution process using a cadmium carboxylate as the precursor at moderate temperatures of 220–300 °C. It was found that the size and morphology of the CdTe NCs were related to synthesis parameters such as the reaction temperature, carboxyl chain length and carboxylic acid. Based on these CdTe NCs, photovoltaic cells (PVC) in simple Schottky diode configuration of ITO/CdTe/Al were fabricated. The performances of the CdTe NCs solar cells were found to strongly rely on the morphology and surface ligand of the CdTe NCs. The best device could show a power conversion efficiency (PCE) of 5.15% under AM 1.5G illumination at 100 mW cm−2, which is the highest efficiency of a CdTe NC-based Schottky solar cell reported to date. Notably, in comparison to the ITO/CdTe/LiF/Al device, the device configuration of ITO/CdTe/Al showed higher efficiency and better air-stability.

Ag2+δSexTe1−x (x = 0–1) nanocrystals (NCs) with different Se and Te content are prepared by a simple hydrothermal process using a SexTe1−x NC template. Both rod- and dot-shaped NCs are obtained, a variation from the rod-shaped SexTe1−x template. The Ag2+δSexTe1−x NC thin films are dense with an atomic ratio δ between Ag and SexTe1−x that can be controlled in the range of δ = 0.1–0.3. The MR effect of Ag2+δSexTe1−x NCs is found to be related to the composition as well as annealing temperature. MR of the Ag2.2Se0.2Te0.8 NC thin films shows a rapid increase to 68% at 239 K and 8 T, an observation providing very useful fundamental information necessary for future applications in the fabrication of high-quality MR sensors and other electronic devices.Graphical abstractHighlights► The first report on the magnetic resistance (MR) properties of Ag2+δSexTe1−x NCs thin films. ► The MR effect of NCs thin films is found to be related to the composition as well as annealing conditions. ► Resistance measurement results imply that these materials have positive MR effect under applied magnetic field ► MR of the Ag2.2Se0.2Te0.8 NC thin films shows a maximum value of 68% at 239 K and 8 T.

We have developed an ITO/ZnO/CdSe/CdTe:CdSe/CdTe/Au novel device architecture based on solution processed CdTe and CdSe nanocrystals (NCs). The introduced hybrid CdTe:CdSe layer was made by mixing different NCs in solution, which allowed for tailoring the optoelectronic properties of the nanocomposite materials. Our novel devices demonstrated more than 30% improvement in Jsc compared with their bilayer analogue, resulting from suppressed recombination. The champion device showed a 6.25% PCE, which is a record for solution processed CdTe:CdSe p–n junction solar cells with the inverted structure. Most important of all, the devices showed extreme stability after storage for three days when maintained under ambient conditions, and less than 3% degradation was observed in PCE after 50 days of storage.

CdTe/CdSe nanocrystal (NC) solar cells with an inverted structure (ITO/ZnO/CdSe/CdTe/Au) have been successfully fabricated by a simple solution process coupled with layer-by-layer sintering techniques. It was found that the device performance is strongly dependent on the annealing strategy, the thickness of the acceptor layer and on the buffer layer of ZnO when the optimal thickness of CdTe is adopted. Without the ZnO buffer layer, a thin film of the CdSe NCs on an ITO substrate shows a rougher morphology, resulting in device shunting. However, when a 40 nm-thick ZnO buffer layer and 60 nm-thick CdSe were employed, the device shows a much higher PCE of 5.81% under device conditions, post-annealing at 340 °C. This value is the highest efficiency ever reported to date for a CdTe/CdSe NC solar cell. Comparing with CdTe/CdSe NC solar cells with the normal device configuration, this device with an inverted structure simultaneously offers good Ohmic contact for carrier collection and efficient harvesting of solar photons in a wide wavelength.

We report the synthesis of CdTe semiconductor nanocrystals (NCs) with multi-armed, rod and tetrapod shapes, developed by a facile solution process using a cadmium carboxylate as the precursor at moderate temperatures of 220–300 °C. It was found that the size and morphology of the CdTe NCs were related to synthesis parameters such as the reaction temperature, carboxyl chain length and carboxylic acid. Based on these CdTe NCs, photovoltaic cells (PVC) in simple Schottky diode configuration of ITO/CdTe/Al were fabricated. The performances of the CdTe NCs solar cells were found to strongly rely on the morphology and surface ligand of the CdTe NCs. The best device could show a power conversion efficiency (PCE) of 5.15% under AM 1.5G illumination at 100 mW cm−2, which is the highest efficiency of a CdTe NC-based Schottky solar cell reported to date. Notably, in comparison to the ITO/CdTe/LiF/Al device, the device configuration of ITO/CdTe/Al showed higher efficiency and better air-stability.