Versatile aza‐BODIPY‐based low‐bandgap conjugated small molecule for light harvesting and near‐infrared photodetection

Abstract

The versatile nature of organic conjugated materials renders their flawless integration into a diverse family of optoelectronic devices with light-harvesting, photodetection, or light-emitting capabilities. Classes of materials that offer the possibilities of two or more distinct optoelectronic functions are particularly attractive as they enable smart applications while providing the benefits of the ease of fabrication using low-cost processes. Here, we develop a novel, multipurpose conjugated small molecule by combining boron-azadipyrromethene (aza-BODIPY) as electron acceptor with triphenylamine (TPA) as end-capping donor units. The implemented donor-acceptor-donor (D-A-D) configuration, in the form of TPA-azaBODIPY-TPA, preserves ideal charge transfer characteristics with appropriate excitation energy levels, with the additional ability to be used as either a charge transporting interlayer or light-sensing semiconducting layer in optoelectronic devices. To demonstrate its versatility, we first show that TPA-azaBODIPY-TPA can act as an excellent hole transport layer in methylammonium lead triiodide (MAPbI 3 )-based perovskite solar cells with measured power conversion efficiencies exceeding 17%, outperforming control solar cells with PEDOT:PSS by nearly 60%. Furthermore, the optical bandgap of 1.49 eV is shown to provide significant photodetection in the wavelength range of up to 800 nm where TPA-azaBODIPY-TPA functions as donor in

Stability, reliability, and performance of organic light-emitting diodes and photodetectors in optogenetic studies

“…Since the discovery of conductive plastics 17 , the field of organic optoelectronics has grown tremendously, producing the next-generation of solar panels 18 , as well as reliable lighting and screen technology that incorporate organic light-emitting diodes (OLEDs) 19 . Organic photodetectors (OPDs) 20,21 and transistors (OFETs) 22 have also shown a tremendous potential in biosensing applications 23,24 . With regard to neuroscience, carbon-based organic materials show remarkable levels of conductivity and biocompatibility and are therefore ideal candidates to mitigate the inflammatory response and improve recording performance in vivo 25,26 .…”

Low bandgap donor-acceptor-donor-based TPA-azaBODIPY-TPA small molecule for flexible near-infrared organic photodetectors

“…Indeed, a boron atom at the core and two pyrrole rings give rise to the BODIPY distinctive characteristics such as strong absorption and excellent photostability [15][16][17] . In our recent work, we used a novel strategy to tune the optoelectrical properties of boron-azadipyrromethene (aza-BODIPY) 18 dye by attaching triphenylamine (TPA) as donor unit groups on each end, to form a donor-acceptor-donor small molecule 18 . The newly synthesized material, TPA-azaBODIPY-TPA (Figure 1a), showed a redshift in absorption up to 800 nm, optimal charge transfer characteristics and excitation energy levels.…”

“…The newly synthesized material, TPA-azaBODIPY-TPA (Figure 1a), showed a redshift in absorption up to 800 nm, optimal charge transfer characteristics and excitation energy levels. Importantly, excellent solubility and processability were retained in the process 18 . The material versatility was demonstrated by proving its effectiveness as a hole transport layer in solar cells, where it replaced a well-known poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS).…”

“…The material versatility was demonstrated by proving its effectiveness as a hole transport layer in solar cells, where it replaced a well-known poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS). In solar cells, TPA-azaBODIPY-TPA-based solar cells showed a remarkable power conversion efficiency of 17% along with robust thermal stability 18 . We also demonstrated the use of this novel semiconducting material as an electron donor in nearinfrared (NIR) OPDs 18 , here forming an active layer together with [6,6]-Phenyl-C71-butyric acid methyl ester, PC71BM.…”

“…We also demonstrated the use of this novel semiconducting material as an electron donor in nearinfrared (NIR) OPDs 18 , here forming an active layer together with [6,6]-Phenyl-C71-butyric acid methyl ester, PC71BM. The resulting OPDs showed a high responsivity of 68 mA W -1 in the NIR range (730 nm) 18 . Combining both solar and photodetection performance, TPA-azaBODIPY-TPA featuring an optical bandgap of 1.49 eV has proven to be a perfect candidate for devices requiring high absorption in NIR.…”