树枝状分子应用于有机电致发光材料的研究进展

有机电致发光材料是光电信息功能材料领域的研究热点之一。相对于线性的有机小分子和高分子,作为有机电致发光材料,树枝状分子有着多方面的优势。分别从树枝状分子作为发光材料、电子传输材料、空穴传输材料和多功能载流子传输材料等4个方面简要介绍了树枝状分子在有机电致发光材料领域的研究进展,并进一步展望了树枝状分子未来的研究前景。

Developing near-infrared quantum-dot light-emitting diodes to mimic synaptic plasticity

The quantum-dot light-emitting diodes(QLEDs)that emit near-infrared(NIR)light may be important optoelectronic synaptic devices for the realization of artificial neural networks with complete optoelectronic integration.To improve the performance of NIR QLEDs,we take advantage of their low-energy light emission to explore the use of poly(3-hexylthiophene)(P3 HT)as the hole transport layer(HTL).P3 HT has one of the highest hole mobilities among organic semiconductors and essentially does not absorb NIR light.The usage of P3 HT as the HTL indeed significantly mitigates the imbalance of carrier injection in NIR QLEDs.With the additional incorporation of an interlayer of poly[9,9-bis(3’-(N,N-dimethylamino)propyl)-2,7-flourene]-alt-2,7-(9,9-dioctylfluorene)],P3 HT obviously improves the performance of NIR QLEDs.As electroluminescent synaptic devices,these NIR QLEDs exhibit important synaptic functionalities such as short-and long-term plasticity,and may be employed for image recognition.

Graphdiyne oxide-accelerated charge carrier transfer and separation at the interface for efficient binary organic solar cells

Interfacial engineering for the regulation of the charge carrier dynamics in solar cells is a critical factor in the fabrication of high-efficiency devices.Based on the successful preparation of highly dispersible graphdiyne oxide(GDYO)with a large number of functional groups,we fabricated organic solar cells employing GDYO-modified poly(3,4-ethylenedioxythiophene)/poly(styrene sulfonate)(PEDOT:PSS)as hole transport materials.Results show that theπ±πinteraction between GDYO and PEDOT:PSS is beneficial to the formation of an optimized charge carrier transfer channel and improves the conductivity and charge carrier mobility in the hole transport layer.Moreover,the improved interfacial contact contributes to the suppression of charge carrier recombination and the elevation of charge carrier extraction between the hole transport layer and the active layer.More importantly,the occurrence of charge carrier separation benefits from the optimized morphology of the active layer,which efficiently improves the performance,as proven by the results of transient absorption measurements.Therefore,with the holistic management approach to the multiobjective optimization of the charge carrier dynamics,a photoelectric conversion efficiency of 17.5%(with the certified value of 17.2%)is obtained for binary organic solar cells.All of these results indicate the potential application of the functionalized graphdiyne in the field of organic optoelectronic devices.

Recent progress of interconnecting layer for tandem organic solar cells

This paper has reviewed:(1) the two unique advantages of tandem organic solar cells(OSCs) compared to single OSCs;(2) the challengings as well as strategies to develop qualified interconnecting layer(ICL) for tandem OSCs.More specifically,firstly,the two key advantages unique to tandem OSCs as compared to single OSCs,namely minimizing sub-bandgap transmission and thermalization loss as well as realizing optical thick and electrical thin structures,have been discussed.Secondly,the ICL,as one of the most challenging issue in tandem OSCs that needs to fulfill the optical,electrical and mechanical requirements simultaneously to realize a qualified ICL has been reviewed.As one of the most challenging requirement among the three,the electrical requirement and its corresponding three different solving strategies have been discussed in detail,revealing a bright future for developing a general strategy to realizing qualified ICL composed of different hole transporting layer(HTL) and electron transporting layer(ETL).

Optimizing the component ratio of PEDOT:PSS by water rinse for high efficiency organic solar cells over 16.7%

For the state-of-the-art organic solar cells(OSCs),PEDOT:PSS is the most popularly used hole transport material for the conventional structure.However,it still suffers from several disadvantages,such as low conductivity and harm to ITO due to the acidic PSS.Herein,a simple method is introduced to enhance the conductivity and remove the additional PSS by water rinsing the PEDOT:PSS films.The photovoltaic devices based on the water rinsed PEDOT:PSS present a dramatic improvement in efficiency from 15.98%to 16.75%in comparison to that of the untreated counterparts.Systematic characterization and analysis reveal that although part of the PEDOT:PSS is washed away,it still leaves a smoother film and the ratio of PEDOT to PSS is higher than before in the remaining films.It can greatly improve the conductivity and reduce the damage to substrates.This study demonstrates that finely modifying the charge transport materials to improve conductivity and reduce defeats has great potential for boosting the efficiency of OSCs.

Eliminating the electric field response in a perovskite heterojunction solar cell to improve operational stability

Intrinsic and extrinsic ion migration is a very large threat to the operational stability of perovskite solar cells and is difficult to completely eliminate due to the low activation energy of ion migration and the existence of internal electric field.We propose a heterojunction route to help suppress ion migration,thus improving the operational stability of the cell from the perspective of eliminating the electric field response in the perovskite absorber.A heavily doped p-type(p^(+))thin layer semiconductor is introduced between the electron transporting layer(ETL)and perovskite absorber.The heterojunction charge depletion and electric field are limited to the ETL and p^(+)layers,while the perovskite absorber and hole transporting layer remain neutral.The p^(+)layer has a variety of candidate materials and is tolerant of defect density and carrier mobility,which makes this heterojunction route highly feasible and promising for use in practical applications.

Simulation Study of the Electron and Hole Transport in a CNTFET

In this work we have investigated electron and hole transport through zig zag carbon nanotubes by solving Boltzmann Transport Equation(BTE).We find that the mobility of electrons is rather greater than holes.Carbo nanotubes with longer diameter can carry higher current.Normally,transport of electrons(or holes) is dominated by scattering events,which relax the carrier momentum in an effort to bring the conducting material to equilibrium.