The performance of lead-halide perovskite light-emitting diodes (LEDs) has increased rapidly in recent years. However, most reports feature devices operated at relatively small current densities (<500 mA/cm 2 ) with moderate radiance (<400 W/sr•m 2 ). Here, Joule heating and inefficient thermal dissipation are shown to be major obstacles towards high radiance and long lifetime. Several thermal management strategies are proposed in this work, such as doping charge-transport layers, optimizing

be grown epitaxially on specific substrates, silicon not being one of them.Metal halide perovskite light-emitting diodes (PeLEDs) hold the potential for a new generation of display and lighting technology, [1][2][3][4][5][6][7] featuring high color quality, energy efficiency, and low manufacturing cost. Furthermore, perovskites can be deposited from solutions/inks, which means that they can be deposited on virtually any substrate including silicon. Perovskite LEDs have been shown to be promising for optical communications. [8] However, the operation speed of PeLEDs is still relatively slow, with electroluminescence (EL) rise times of several hundred nanoseconds or longer. [9][10][11][12] The slow operation speed and response time of PeLEDs limit their potential for a wider scope of applications, such as interchip and intrachip optical communications, currently realized with more expensive technologies using III-V semiconductors.Reducing the EL rise time of PeLEDs will not only increase their potential utility for applications in optical communications, but also contribute to the development of an electrically driven perovskite laser diode, which would be transformative in the optoelectronics realm as a low-cost laser source compatible with silicon microelectronics. Despite significant progress toward this goal, [13][14][15][16] electrically driven lasing in perovskites has not yet been achieved. One challenge is that the current density reported to date does not exceed the estimated threshold required for lasing. Reducing the EL rise time would enable shorter pulse operation, making it possible for PeLEDs to operate at higher current densities due to reduced Joule heating. [10,17] Furthermore, high-speed pulsed operation of PeLEDs will allow us to probe electrically stimulated chargecarrier dynamics and reveal mechanisms that prevent PeLEDs from operating efficiently or lasing under electrical excitation. This understanding is particularly important as optically pumped lasing death has been observed for perovskite thin films within 25 ns, [18] and optical and electrical excitations are considerably distinct.Both extrinsic factors (e.g., parasitic capacitance and resistance) and intrinsic factors (e.g., long recombination lifetime of charge carriers in the light-generating process) can limit the speed of PeLEDs. However, the speed of PeLEDs reported so far appears to have been dominantly constrained by extrinsic factors, [8][9][10][11][12] excluding the possibility to probe more intrinsic While metal-halide perovskite light-emitting diodes (PeLEDs) hold the potential for a new generation of display and lighting technology, their slow operation speed and response time limit their application scope. Here, high-speed PeLEDs driven by nanosecond electrical pulses with a rise time of 1.2 ns are reported with a maximum radiance of approximately 480 kW sr −1 m −2 at 8.3 kA cm −2 , and an external quantum efficiency (EQE) of 1% at approximately 10 kA cm −2 , through improved device configuration designs and material consi...

Crystallization from solutions containing 2,2′-[naphthalene-1,8:4,5bis(dicarboximide)-N,N′-diyl]-bis(ethylammonium) diiodide ((NDIC2)I 2 ) and PbI 2 has been investigated. Eight different materials are obtained, either by variation of crystallization conditions or by subsequent thermal or solvent-induced transformations. Crystal structures have been determined for five materials. 5) form 1-dimensional (1D) chains consisting of PbI 6 (and, in the case of 1, PbI 5 (DMF)) octahedra, either solely facesharing or a mixture of face-sharing and vertex-sharing. The structure of [(NDIC 2 ) 3 Pb 5 I 16 ]•6NMP (2) contains 0D clusters; these consist of three PbI 6 octahedra and two unusually coordinated lead centers that exhibit three relatively short Pb−I bonds, two very long Pb−I contacts, and η 2 -coordination of an aromatic ring of NDIC2 to the lead. Close contacts between iodide ions and the imide rings of NDIC2 in four of the structures suggest that an iodide-to-NDIC2 charge-transfer interaction may be responsible for the observed red coloration of the materials. The optical and electrical properties of 1 have been studied; its onset of absorption is at 2.0 eV, and its conductivity was measured as 5.4 × 10 −5 ± 1.1 × 10 −5 S m −1 .

n-i-p perovskite devices based on NDI materials are fabricated to demonstrate utility of a transparent polymer vs. that of several small molecules with varied acceptor strengths; stable solar cells with 14% PCE are reported.