With rapid development of 5G communication technologies, electromagnetic interference (EMI) shielding for electronic devices has become an urgent demand in recent years, where the development of corresponding EMI shielding materials against detrimental electromagnetic radiation plays an essential role. Meanwhile, the EMI shielding materials with high flexibility and functional integrity are highly demanded for emerging shielding applications. Hitherto, a variety of flexible EMI shielding materials with lightweight and multifunctionalities have been developed. In this review, we not only introduce the recent development of flexible EMI shielding materials, but also elaborate the EMI shielding mechanisms and the index for "green EMI shielding" performance. In addition, the construction strategies for sophisticated multifunctionalities of flexible shielding materials are summarized. Finally, we propose several possible research directions for flexible EMI shielding materials in near future, which could be inspirational to the fast-growing next-generation flexible electronic devices with reliable and multipurpose protections as offered by EMI shielding materials.

heat engines and transforming the asgenerated mechanical energy into electricity. [2][3][4][5] Compared with traditional unsustainable method, thermoelectric materials, which can transform the temperature gradient from waste heat or solar thermal energy into electricity through the Seebeck effect, have triggered great interest in the development of wearable cooling/heating devices and low-temperature energy generators. [6][7][8][9][10][11][12][13][14][15][16][17] Inorganic thermoelectric materials exhibit superior thermoelectric figure of merit than the organic ones, but their low abundance, high-cost, heaviness, and brittleness usually prevents their applications for flexible and/or nontoxic devices. [18][19][20][21][22][23][24] In contrast, organic thermoelectric materials present intrinsically low thermal conductivity and high mechanical flexibility, making them versatile in green energy harvesting and thermoelectric refrigeration (Figure 1). [25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42] The energy conversion efficiency of the thermoelectric materials can be estimated by the dimensionless figure of merit ZT = S 2 σT/κ, where S is the thermopower or Seebeck coefficient, σ is electrical conductivity of materials, T is the absolute temperature, and κ represents the thermal conductivity. [43][44][45][46][47][48][49][50][51] Superficially, increasing S and σ, and decreasing κ can infinitely raise the value of ZT. However, the strong interdependence among these three parameters is extremely challenging. [52][53][54][55][56] Over the past years, scientists have managed to increase the ZT values of organic thermoelectric materials via molecular design, phonon, and electron transport decoupling, and production of hybrid composites incorporating high thermoelectric particles. [57][58][59][60][61][62][63][64][65][66][67][68][69] In this review, the thermoelectric performances of the organic single-component materials, hybrid composites, and novel ionogels developed over the last several years are discussed separately in terms of the respective parameter tuning and pathway optimization. The current state of the art of organic thermoelectric materials is primarily highlighted based on their structure-property relationship. In particular, the marvelous progress that has allowed organic thermoelectric materials to compete with traditional inorganic compounds is described. Finally, organic thermoelectric generators containing different legs with variousoutput powers and their multiple applications are briefly summarized.The enormous demand for waste heat utilization and burgeoning ecofriendly wearable materials has triggered huge interest in the development of thermoelectric materials that can harvest low-cost energy resources by converting waste heat to electricity efficiently. In particular, due to their high flexibility, nontoxicity, cost-effectivity, and promising applicability in various fields, organic thermoelectric materials are drawing more attention compared with their toxic, expensive, he...

No abstract

MXenes, a new class of two-dimensional materials with excellent performance, are promising materials for wearable energy storage devices. However, the lack of sufficient interaction between various MXene particles makes it...