To improve the efficiency of perovskite solar cells, careful device design and tailored interface engineering are needed to enhance optoelectronic properties and the charge extraction process at the ...selective electrodes. Here, we use two-dimensional transition metal carbides (MXene Ti
C
T
) with various termination groups (T
) to tune the work function (WF) of the perovskite absorber and the TiO
electron transport layer (ETL), and to engineer the perovskite/ETL interface. Ultraviolet photoemission spectroscopy measurements and density functional theory calculations show that the addition of Ti
C
T
to halide perovskite and TiO
layers permits the tuning of the materials' WFs without affecting other electronic properties. Moreover, the dipole induced by the Ti
C
T
at the perovskite/ETL interface can be used to change the band alignment between these layers. The combined action of WF tuning and interface engineering can lead to substantial performance improvements in MXene-modified perovskite solar cells, as shown by the 26% increase of power conversion efficiency and hysteresis reduction with respect to reference cells without MXene.
We demonstrate that the halide perovskite planar solar cells with the architecture of ITO/PEDOT:PSS/Perovskite/PCBM/LiF/Al show a switchable dual operation of descent photovoltaic and quite bright ...electroluminescence in visible range. In our experiments, the active layer is made of a mixed halide perovskite (MAPbBr2I) and the device is properly cycled upon light and bias exposure. We argue that this curious effect of switchable double functionality between solar cell and light-emitting device in one architecture is caused by photoinduced segregation in the perovskite. It is shown that the bright red electroluminescence at low voltage of ∼ 2 (3) eV appears only after cycling the device in PV regime. On the other hand, electroluminescence operation also effects the following PV mode. This effect is caused by redistribution of photoactivated ions I-/Br- and their vacancies during photoexcitation in PV regime.
In this work we demonstrate the beneficial role of MXene doping for both perovskite absorber and electron transporting layer in NiO-based inverted perovskite solar cells. The addition of MXenes ...permits on one side to easy tune the energy level alignment at perovskite/charge transporting layer interfaces, and on the other side to passivate traps states within the cell structure, which in turn improves charge extraction and collection at the electrodes. The MXene-based engineered cells showed superior performance, with power conversion efficiency exceeding 19% and improved stabilized power output with respect to reference devices. Due to the possibility to finely tune the MXene work function during their chemical synthesis and to their capability in modifying the optoelectronic properties of PSC layers when used as dopant, the proposed approach opens countless ways for engineering inverted PSC structure, strongly promising in term of long-term stability and future scalability on large area devices.
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•MXenes are employed to engineer the inverted p-i-n perovskite solar cell (PSC) structure based on nickel-oxide hole transporting layer.•Ti3C2Tx are exploited to modify the work function of p-i-n PSC constituting layers and their band alignments.•MXenes addition into perovskite absorber and electron transporting layer improves efficiency up to 19.2% by hampering charge recombination.•The WF tunability of MXenes is suggested as a general approach for boosting inverted PSC PCE over the current state of art.
The possibility of molecular structural design provides a wide field for engineers to generate interest to heterocyclic structures based on die-perylene and naphthoyl, the possible combinations for ...the superposition of the absorption spectra. From this point of view, the creation of optically active polymers based on polybenzomidazofenantroline (PBF), 1, 4, 5, 8- naphthalene tetracarboxylic and 3, 4, 9, 10- perylenetetracarboxylic acids opens new opportunities in this important field of science and technology. The results are high absorption in visible spectrum and ability of morphology improvement. Advantages in the optical properties PPBI-O and PNBI-O above the target prototype P3HT, namely a peak absorption in the region of 555 nm to 700 nm red edge are detected.
The main issue is to determine the allowable concentration of the polymer and the acceptor, allowing to obtain a film having a desired density and at the same time, the thickness, the optimum from ...the point of view of the diffusion length and the probability of dissociation of the intermediate particles with the formation of free charge carriers. From a comparison of the synthesized samples micrographs it can be concluded that the polymer concentration of 12.5 g/l gives a sufficiently dense and relatively uniform film without substantial amounts of undissolved polymer.
Interface engineering is one of the most critical directions in the development of photovoltaics (PVs) based on halide perovskites. A novel triphenylamine-based hole transport material (HTM) with a ...carboxyl anchoring group (TPATC) was developed for tuning the interface between nanocrystalline NiO and CsCH3(NH2)2PbI3-xClx absorber in p-i-n device architectures. Transient spectroscopy measurements revealed that modification of the NiO surface with TPATC in perovskite solar cells (PSCs) reduces the concentration of ionic defects by an order of magnitude and reconfigures the energy levels of traps. Interface engineering allowed to reach power conversion efficiency of 20.58% for small area devices (0.15 cm2) under standard AM 1.5 G conditions. Using TPATC interlayer also provided sustainability of the perovskite absorber to decomposition under operation conditions. After continuous light-soaking (ISOS-L-2 protocol), NiO/TPATC devices showed a slight decrease of 2% in maximum power. We explored the potential of TPATC to modify interfaces in perovskite solar modules (PSM, active area-64.8 cm2). By applying slot-die-coated TPATC, the PCE at AM 1.5 G conditions increased from 13.22% for NiO PSM to 15.64% for NiO/TPATC ones. This study provides new insights into the interface stabilization for perovskite solar cells, behavior of the ionic defects and their contribution to the long-term stability.
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•A novel triphenylamine-based self-assembling material (SAM) for p-type interface.•Carboxyl anchoring group provides traps passivation at NiO/perovskite junction.•Quantitative analysis of the defect parameters in the device with SAM.•Improvement was validated for perovskite solar modules with efficiency – 15.64%.•Interface engineering improves phase stability of perovskite thin-films.
The new concept of an electronic tunable device based on nanostructured materials is suggested. A tunable organic diode is represented by the example of a vertical architecture with a polymer layer ...of poly-3 hexylthiophene-P3HT and an upper carbon electrode whose properties vary in a wide range when it is doped in a double electric layer in an ionic liquid. Two types of ionic liquids with different ion sizes and different breakdown voltages are used. It is shown that diode based on nanotubes plus organic can be used for photodetectors and in photovoltaic elements
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