Spontaneous transitions to enhanced fluorescence for GeV centers in a single microcrystalline diamond

We propose a theoretical explanation of spontaneous transitions between dim and bright fluorescence intensity states observed experimentally in a microcrystal of diamond with germanium-vacancy colour centres driven by a continuous wave laser. We use a generalized system of optical Maxwell-Bloch equations derived for an emitter in an ensemble of motionless similar particles embedded in a dielectric medium, which is transparent for the incident light. A numerical analysis of transient regimes and several models of slow damping of the bright luminescence mode are reported

Spontaneous transitions to enhanced fluorescence for GeV centers in a single microcrystalline diamond

We propose a theoretical explanation of spontaneous transitions between dim and bright fluorescence intensity states observed experimentally in a microcrystal of diamond with germanium-vacancy colour centres driven by a continuous wave laser. We use a generalized system of optical Maxwell-Bloch equations derived for an emitter in an ensemble of motionless similar particles embedded in a dielectric medium, which is transparent for the incident light. A numerical analysis of transient regimes and several models of slow damping of the bright luminescence mode are reported

Novel Push-Pull Benzodithiophene-Containing Polymers as Hole-Transport Materials for Efficient Perovskite Solar Cells

Donor-acceptor conjugated polymers are considered advanced semiconductor materials for the development of thin-film electronics. One of the most attractive families of polymeric semiconductors in terms of photovoltaic applications are benzodithiophene-based polymers owing to their highly tunable electronic and physicochemical properties, and readily scalable production. In this work, we report the synthesis of three novel push–pull benzodithiophene-based polymers with different side chains and their investigation as hole transport materials (HTM) in perovskite solar cells (PSCs). It is shown that polymer P3 that contains triisopropylsilyl side groups exhibits better film-forming ability that, along with high hole mobilities, results in increased characteristics of PSCs. Encouraging a power conversion efficiency (PCE) of 17.4% was achieved for P3-based PSCs that outperformed the efficiency of devices based on P1, P2, and benchmark PTAA polymer. These findings feature the great potential of benzodithiophene-based conjugated polymers as dopant-free HTMs for the fabrication of efficient perovskite solar cells