With the rapid development of the modern society, people's demand for energy has increased dramatically, and the energy crisis is imminent. To tackle this issue, researchers are committed to improving the utilization of existing energy sources to improve energy conversion efficiency by designing devices with unique structures. The QLEDs (quantum dots light-emitting diodes), piezoelectric nanogenerators and their combination of multifunctional self-powered system are the typical examples. QLEDs have huge application prospects in display and lighting fields, due to their excellent physical properties, such as narrow emission band, wide color space and high luminance and also, the micro-QLED is regarded as the future of display technique. However, QLEDs suffer from two problems that are low efficiency and short lifespan due to large leakage currents. To solve this problem, in the inverted QLEDs, we introduced an organic HATCN polymer (Dipyrazino[2,3-f:2',3'-h] quinoxaline-2,3,6,7,10,11-hexacarbonitrile) interlayer into the device through thermal evaporation technique. The HATCN layer on the one hand can make the carrier transport more efficient and on the other hand protect the organic CPB (4,4'-Bis(N-carbazolyl)-1,1'-biphenyl) from thermal damage with the thermal vapor deposition of MoO3 (molybdenum oxide). By precisely adjusting the thickness of HATCN layer at 6 nm, the problem of thermal damage has been perfectly solved. The leakage current has been reduced and the current efficiency has been increased 18% while maintaining the characteristics of low turn-on voltage and high brightness. Besides, in traditional QLEDs, CuSCN (Copper(I) thiocyanate) interlayer has been introduced in the device to replace PEDOT: PSS (poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate)) to achieve fast hole injection rate. But it simultaneously caused the corrosion problem of ZnO (Zinc oxide) solution to CuSCN. To solve this problem, we introduced a thick PVK polymer (Poly(9-vinylcarbazole)) interlayer through spin coating technique to protect CuSCN. However, a thick PVK (90 nm) hindered carrier transport leading to the reduction of efficiency. To further improve the efficiency, we have carried out the post-annealing treatment to the devices. Through this method, the current efficiency of the device has been increased by 56% and the best post-annealing condition is the temperature of 160℃ and the time of 30 min. Since the efficiency of QLEDs have achieved great progress and building up self-powered system achieving mutilfunctionailties is a brand-new trend for future development. This miniaturized and portable system has the ability to continuously collect the mechanical energy in people's daily motion and convert it into electrical energy to power the system. To achieve this goal, piezoelectric devices should be developed. The PVDF (Poly (vinylidene fluoride)) polymer is the material that is widely used in piezoelectronics, because it is non-toxic, cheap, flexible and has excellent piezoelectric properties. However, PVDF is usually a non-polar α-phase with low piezoelectric response and needs to stimulate to polar β-phase with high piezoelectric response. Therefore, we used our self-built corona poling platform (simpler and more affordable) to increase the β-phase content and piezoelectric coefficient. Through the poling treatment for PVDF, the β-phase content has been increased to 86% and the piezoelectric coefficient is 16.4 pC/N, which is comparable to that reported value in the literature. The piezoelectric device based on PVDF can obtain an output voltage of 3.4 V and can light up a red LED, which is a typical example for self-powered system. In order to further improve its piezoelectric Properties, AgNO3 (Silver nitrate) has been loaded into PVDF to form a composite film. By adjusting the doping concentration, the β-phase has been promoted to 91% and the optimal doping concentration is 1.5 wt.%. The nanogenerator based on the composite film can simultaneously light up 10 blue LEDs and quickly charge a capacitor within less than 10 s, which is a more advanced self-powered system. All in all, this research work provides effective solutions to fabrication high performance QLEDs using polymer films. In addition, it also provides an effective way to enhance the piezoelectric response of device based on PVDF and the composite films. Moreover, the development for self-powered system with multifunctionality paves the way for their application in the fields of soft electronics, human health monitoring and energy harvesting. Key words: Quantum dot light-emitting diodes, Current efficiency, Nanogenerators, PVDF composite films, Piezoelectric property.