A non-doped multi-periodic structure of composite hole transport layer of [MoO3/CBP]n was applied to organic light-emitting diodes.

Perfect sound absorption (PSA), producing an absorption coefficient of 1, can be achieved based upon the coherent interaction of acoustic waves, while it can merely be achieved within a narrow frequency-band due to critical impedance matching conditions. Here, we theoretically and experimentally study self-modulation and active-tunability in PSA created on account of a membrane-covered cavity. It is observed that due to the nonlinearity of the membrane, the frequency of PSA increases with the intensities of input acoustic waves, exhibiting a self-modulation property. Furthermore, we design an apparatus to control the elasticity of the membrane via four electromagnets, and thus, the PSA frequency can be freely and effectively adjusted by changing the direct-current driving voltage of the electromagnets. Despite the critical impedance matching conditions, the absorption coefficient achieved in our system holds at 1 when the PSA frequency is freely changed, which exhibits strong robustness in active-tunability.

Etching residue is a kind of thorny technological issue in the manufacturing of flat panel. In this work, we report on a systematic investigation on anode etching residue which is widely generated in the manufacturing of low temperature polycrystalline Si‐active matrix organic light emitting diode (LTPS‐AMOLED). Firstly, we proposed three kinds of residue formation mechanisms, including the Bernoulli equation‐based dynamic process, as well as two other situations caused by absence of electrochemical accelerated reaction and organic residue in preprocessing, respectively. Then, residue related failure model of product defects was clarified and considered to give rise to ~3.1% product yield loss owing to the related phenomenon named dark line. Finally, we provided three solutions based on the formation mechanism and failure model, and superior process and design implementation conditions were obtained with detailed experimental verifications, which can be promising methods to solve other related issues in the manufacturing to bring cost down.

Organic Light ‐ Emitting Diode (OLED) displays are characterized by ultra‐thin, ultra‐clear, spontaneous light, high definition, low cost of preparation and flexible display. In recent years, flexible OLED has become a hot topic in flat panel display industry. Thin film encapsulation (TFE) plays a key role in flexible OLED [1,2]. The inorganic layer part of flexible encapsulation is generally prepared by plasma enhanced chemical vapor deposition (PECVD) for SiNx or SiON. The quality of inorganic thin film directly affects the service life‐time of OLED devices, It is mainly influenced by Particle, shadow effect, stress, refractive index, thickness and other factors, among which several factors besides the shadow effect of thin films have been widely studied. As we all know, shadow effect exists in any film, but for inorganic layer in flexible encapsulation, whether the shadow effect of the thin film will affect its encapsulation effect. This paper will explore the influence of thin film shadow effect on encapsulation effect and device life. The shadow of the thin film varies from a few microns to several hundred microns in the existing devices. In this paper, a special device structure design is used to control the size of film shadow. We will produce OLED samples of different shadow sizes. It can be seen from the test results in the 85 °C and 85% RH for 240h that the smaller the Shadow of PECVD thin film is, the less likely it is to lose efficacy. In this paper, by effectively controlling the shadow size of the thin film, flexible OLED devices with better performance and longer service life are obtained. At last, more tests are needed in order to get a more precise investigation.