Flexible Opal/Inverse Opal Photonic Crystal Materials And Devices

Photonic crystal(PC)materials have the potential to control and manipulate light due to their unique photonic band gap(PBG)characteristics.They have broad application potentials and are expected to play an important role in detection,communication and medical fields.In the present thesis,a variety of photonic sensors and hybrid devices are designed by combining PC structure with responsive materials or photovoltaic devices,and their application potentials are systematically evaluated.The present research is significant on the design,the application of photonic crystal materials and the application innovation of flexible photonic devices.The main research contents are as follows:(1)Photonic pressure sensorsWe investigated the photonic output modes of three-dimensional photonic crystal(3DPC)coated gel-based pressure sensors and explored their ability to sense low pressures.A sensor with a diameter of 1.0 cm provides good reproductivity and a sensitivity of 0.355 kPa-1 through reflection in the detection range of 0-2.50 kPa,while a smaller sensor with a diameter of 0.7 cm responds to pressure in the range of 0-0.50 kPa but with a sensitivity of 1.834 kPa-1,which is approximately 5 times higher than the sensitivity of the larger sensor.Such sensors with high sensitivity,fast response and adjustable detection range are promising in the development of stimuliresponsive soft materials for future artificial intelligence,health monitoring and photonic communication systems.(2)PC fluorescence collimatorsThe fluorescence emission of organic fluorescent dyes(i.e.,rhodamine 6G(R6G))can be linearly enhanced or inhibited by a photonic crystal(PC)as a result of the photonic band gap(PBG)coupling with the excitation light and emission light.Depending on the design of the PC fluorescence collimator,the emission can reach 49.37 times higher than the control.The PC fluorescence collimator can be applied to achieve significant benefits:for instance,as a humidity sensor,it provides good reproducibility and a sensitivity of 28.50 a.u./%relative humidity(RH),which is 80.78 times higher than the sensitivity of the control,and as a novel curtain,it raises the energy conversion efficiency(ECE)of the semitransparent dye-sensitized solar cells(DSSCs)by 16%.(3)Upconverted PC-coupled photovoltaic devicesWe demonstrate that functionalizing upconversion nanoparticles(UCNPs)in silk materials with PC structure can significantly improve upconversion emission,which can be amplified by 5 times in green light region.By integrating with such upconverted enhanced luminescent silk film,a remarkable enhancement in energy conversion efficiency(ECE)of a single fibrous dye-sensitized solar cell(FDSC)was achieved under infrared radiation,by up to a factor 47.3 compared with the control.This presents a flexible design of wireless charger device composed of an UCNPs functionalized silk film and a photovoltaic device and its further potential NIR-driven implantable medical devices applications.