Ambient Fabrication Of Large-area And Flexible Light-emitting Devices Using Roll-coating

Manufacturing organic electronics via Mayer-rod technique is rather attractive for realizing cost-effective,large-area and facile mass production yet challenging.In this paper,we develop a systematic investigation and optimization of the Mayer-rod coating processing of organic electroluminescent(EL)films.Various factors influencing the Mayer-rod coating film quality,solvent engineering,emitting material concentration,ionic conductor proportion have been systematically investigated and optimized.As a result,uniform large-area electroluminescent polymer films are achieved by Mayer-rod coating.Meanwhile,carbon quantum dots(CQDs)are introduced into the active layer,which guides the ordered arrangement of the polymer,improves the morphology and enhances ion mobility of the film.It is found that the functional groups of CQDs guide the luminescent materials in the film in an order which could reduce the polymers stacking in the process of printing.It can improve the phase separation,make the circular domain of the solid electrolyte aggregate uniform and fine,and ensure the stable transmission of ions.It can interrupt the crystal distribution of PEO,reduce the crystallinity of PEO,and further increase the ion mobility.Moreover,we have designed large-area light-emitting devices with excellent performance.By printing the active layer and evaporating the electrode,the uniform printing of the large-area luminescent film is achieved by means of regulating the secondary flow of the ink by the post-processing process parameters,and the thickness of the printed wet film.The salt concentration in the active layer ink is further regulated to ensure high ion mobility of the large-area luminescent film.The optimized printed luminescent film has excellent comprehensive performance,and the specific performance is that the prepared large-area light-emitting device has uniform illumination and high device efficiency.The device has a uniform illumination time of more than 3 hours in the air without encapsulation,and further realizes stable illumination when the flexible device is lit and bent.In this contribution,we develop a systematic investigation and optimization of the organic functional films formation during printing process,taking the Mayer-rod coating as an example.With the aim to enable facile Mayer-rod coating of uniform and large-area organic functional films fabrication.Various factors on influencing the Mayer-rod coating film quality have been investigated and optimized,such as the Mayer-rod coating processing,solvent engineering,emitting material concentration,the ionic conductor proportion,CQDs concentration,Li~+concentration and post treatment processes.