Saripally Sudhaker Reddy

Highly Efficient Organic Hole Transporting Materials for Perovskite and Organic Solar Cells with Long‐Term Stability

Small molecules based on N-atom-linked phenylcarbazole-fluorene as the main scaffold, end-capped with spirobifluorene derivatives, are developed as organic hole-transporting materials for highly efficient perovskite solar cells (PSCs) and bulk heterojunction (BHJ) inverted organic solar cells (IOSCs). The CzPAF-SBF-based devices show remarkable device performance with excellent long-term stability in PSCs and BHJ IOSCs with a maximum PCE of 17.21% and 7.93%, respectively.

Acridine-based novel hole transporting material for high efficiency perovskite solar cells

An acridine-based hole transporting material (ACR-TPA) without the spirobifluorene motif is synthesized via non complicated steps. The ACR-TPA film including Li-TFSI and 4-tert-butylpyridine (tBP) additives exhibits a hole mobility of 3.08 × 10−3 cm2 V−1 s−1, which is comparable to the mobility of the classical spiro-MeOTAD (2.63 × 10−3 cm2 V−1 s−1), and its HOMO level of −5.03 eV is slightly lower than that of spiro-MeOTAD (−4.97 eV). ACR-TPA layers with different thicknesses are applied to MAPbI3 perovskite solar cells, where power conversion efficiency (PCE) increases as the ACR-TPA layer thickness increases due to increased recombination resistance and fast charge separation. The best PCE of 16.42% is achieved from the ca. 250 nm-thick ACR-TPA, which is comparable to the PCE of 16.26% for a device with spiro-MeOTAD in the same device configuration. It is thus anticipated that ACR-TPA can be a promising alternative to spiro-MeOTAD because of its lower cost and comparable photovoltaic performance.

All Solution-Processed Red Organic Light-Emitting Diodes Based on New Thermally Cross-Linked Heteroleptic Ir(III) Complex

A novel cross-linkable red iridium(III) complex and electron transport material were designed and synthesized for use in the fabrication of solution-processed phosphorescent organic light-emitting diodes (PHOLEDs). The newly cross-linkable red Ir(III) complex was successfully thermal cross-linked with a cross-linkable host in the emitting layer (EML). After cross-linking, the EML was found not to be damaged by organic solvents. A maximum external quantum efficiency (EQE) of 4.64% (2.77 cd A−1) was achieved for deep-red PHOLEDs after rinsing, which was similar to the EQE of 4.59% (2.52 cd A−1) after rinsing the deep-red PHOLEDs with thermal cross-linking.

Solar Cells: Highly Efficient Organic Hole Transporting Materials for Perovskite and Organic Solar Cells with Long-Term Stability (Adv. Mater. 4/2016)

Highly efficient small-molecular organic hole-transporting materials (HTMs) are demonstrated by M. Song, S.-H. Jin, and co-workers on page 686. These HTMs have applications in perovskite solar cells (PSCs) and bulk-heterojunction (BHJ) inverted organic solar cells (IOSCs) based on N-atom-linked phenylcarbazole-fluorene as the main scaffold, end capped with spirobifluorene derivatives. One of the HTM CzPAF-SBF-based devices shows remarkable device performance with excellent long-term stability in PSCs and BHJ IOSCs with maximum PCE values of 17.21% and 7.93%, respectively.