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affects both its electrical conductivity and its absorption spectrum. These changes have obvious application as a sensor of relative humidity (RH).Structural colors found in nature [9] have received great scientific interest and been reproduced by diverse structural colors. [10][11][12] The simplest structural coloration mechanism consists of planar multilayered arrangements. [13][14][15][16][17] In particular, the metal-insulator-metal (MIM) configuration based on a Fabry-Pérot resonator has a high quality factor efficient band-pass filtering with scalability and cost-effective fabrication. [18][19][20] However, conventional planar MIM resonators lack tunable function, because the resonance depends only on the geometry and optical parameters of the insulating layer.Structural colors have been tuned using chemical, [21][22][23][24][25][26] mechanical, [27,28] or electrical stimuli, [29,30] polarization, [31,32] and phase-change materials. [33] However, tunable structural colors have a slow response, [21] complicated mechanism [27,28,33] and insufficient dynamic change. For those reasons, practical application of structural colors has been limited.In this work, we propose tunable color filter composed of MIM multilayer, in which the insulator is chitosan hydrogel. This color filter can serve as a humidity sensors when combined with a photovoltaic (PV) cell. The structure uses chitosan film sandwiched between two ultrathin silver (Ag) layers deposited on a glass substrate. The key element is the chitosan insulating layer, in which the effective optical thickness t eff and refractive index n c change in response to RH; this trait can be exploited to obtain optical tunability of the resonance wavelengths. The corresponding resonance peak shift induces output current change of a PV cell, which is proportional to a change in the RH value of the environment. The special features of the proposed sensor are simple development, incorporation into PV cell, and potentially zero power usage, that make it a promising material for devices that monitor RH in enclosed spaces, workplaces and storage areas. Results and Discussion Transfer-Matrix Method (TMM) Simulation of Ag-Chitosan-Ag Multilayer StructuresWe present a tunable MIM bandpass filter in which the sensitive insulating layer is composed of chitosan, which can adsorb A tunable Fabry-Pérot resonator is realized using metal-insulator-metal structure, in which the insulator is chitosan hydrogel. The chitosan swells in response to changes in relative humidity; this change affects transmissive structural color of the multilayer structure. This tunable resonator is utilized for a humidity sensor combined with a photovoltaic cell. The change in current through the photovoltaic cell provides rapid precise measurement of relative humidity, and the change in color of the multilayer provides an approximate, remotely-readable estimate. The response requires no power, so the device has numerous sensing applications.

The paper-and-pencil programming strategy (PPS) is a way of representing an idea logically by any representation that can be created using paper and pencil. It was developed for non-computer majors to improve their understanding and use of computational thinking and increase interest in learning computer science. A total of 110 non-majors in their sophomore year were assigned to either a Logo or a PPS course with attendance being 2 hours per week for 15 weeks. To measure the effectiveness of PPS, the Group Assessment of Logical Thinking and a self-assessment survey preand post-test were used. Findings indicated that PPS not only improved students' overall logical thinking as much as did Logo programming learning, but also increased scores on one more subscale of logical thinking than did the Logo course. In addition, PPS significantly helped students understand the concept of computational thinking and increased their interest in learning computer science.Computer science (CS) has led to innovations in society and daily life. However, the public's interest in CS has decreased (Carter

of two different materials. [7,[16][17][18][19] It also enables the hybrids to inherit the superior mechanical flexibility of organic materials. [20,21] Since the first CQD/ organic hybrid solar cells were proposed, [22] efforts have been underway to improve the PCE. Although many previous studies successfully demonstrated complementary absorption, the PCEs of hybrid solar cells are still affected by inefficient charge extraction, caused by 1) the short exciton diffusion length in polymers, [19] 2) poor nanomorphology of the CQD:polymer mix causing unfavorable charge transfer pathways, and 3) local trap sites at the interfaces of CQD and polymer. [18] Various strategies such as exploration of new materials for use in the hybrids, [23][24][25][26][27] tuning CQD size, [18,28] molecular modification, [18,29] and ligand exchange [30,31] have been proposed to enhance the charge extraction in CQD/polymer hybrids. Among them, tuning the CQD surface using organic/inorganic ligands has been widely investigated because it can modify the CQD surface that affects the electrical properties. [16,32,33] Recently, a small-molecule bridge was employed in CQD/ organic hybrid solar cells to overcome the short exciton diffusion length problem; [34,35] however, the hybrid cells still suffer from substantial trap sites at the CQD/organic interfaces, limiting charge extraction. The CQD/organic interfaces have many trap sites due to the large difference in surface energy between the CQD and polymer, [18] the presence of insulating ligands, [16] and defects on the CQD surfaces. [36] These CQD/polymer interfaces potentially hinder charge transport and induce bimolecular recombination.In this work, we systematically investigated how the CQD/ organic interfaces influenced the charge transport properties. First, we replaced the native ligand of CQD with halides to form conventional CQD solids. [37] Subsequently, a polymer layer was stacked onto the CQD solid to form a CQD/organic heterointerface. Additionally, an auxiliary interfacial layer passivated by various organic ligands was implemented at the CQD/polymer interface. The interfacial layer that provides the cascading conduction band offset (ΔE C ) between CQD and polymer relieved band bending that adversely hinders the charge transfer at CQD/polymer interfaces. The reduced band bending facilitated the charge transfer across the heterojunction by suppressing charge accumulation -as confirmed by transient photocurrent (TPC) spectroscopy -and by reducing bimolecular recombination at the CQD/polymer interfaces.Emerging semiconducting materials including colloidal quantum dots (CQDs) and organic molecules have unique photovoltaic properties, and their hybridization can result in synergistic effects for high performance. For realizing the full potential of CQD/organic hybrid devices, controlling interfacial properties between the CQD and organic matter is crucial. Here, the electronic band between the CQD and the polymer layers is carefully modulated by inserting an interfacial layer treated...

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