The interactions within CdS/CTS were further characterized using XPS (Figure ). XPS elemental survey shows elements of Cd 3d5, Na 1s, O 1s, S 2p, and C 1s binding energy (BE) of 409.1 eV, 1077.1, 540.1, 166.1, and 288.1 eV, respectively (Figure ). N 1s is overlapped with Cd 3d5/2. However, the overlap between the N1s and Cd 3d5/2 region can be resolved with peak fitting. Cl 2p at a binding energy of 202.1 eV indicates that Na 1s is due to ubiquitous salt, i.e., NaCl. C 1s spectrum shows peaks at BEs of 284.8 eV, 286.4 eV, and 289.2 eV, referring to C-C, C-O-C, and C(N)-C=O, respectively (Figure ). N 1s spectrum shows peaks at BEs of 404.7 eV and 404.0 eV (Figure ). The analysis of O 1s shows peaks at BEs of 531.6 eV, 535.8 eV, and 536.6 eV corresponding to C-O, C=O, and Na KLL Auger, respectively (Figure ). XPS spectrum for Cd 3d5/2 shows peaks at 404.8 eV, and 411.5 eV corresponding to Cd 3d5/2 and Cd 3d3/2, respectively (Figure ). The analysis of Cd 3d confirms the presence of CdS. The small peak at a binding energy of 410.7 eV is due to the interaction of CdS and the functional groups of CTS (Figure ). The S 2p shows a peak at 161.1 eV and 162.4 eV assigned to S 2p3/2 and S 2p1/2, respectively (Figure ). The peak at BE of 168.5 eV is due to the oxidized S, i.e., SO3 2-or SO4 2-on the external surface of CdS (Figure ). XPS analysis confirms the successful formation of CdS/CTS with the interaction between the CdS core and the functional groups of CTS (Figure ). TEM and HR-TEM images confirm the presence of nanocrystals with a particle size of 1-7 nm with clear lattice fringes due to high crystallinity (Figure ). TEM images show a uniform distribution of CdS inside chitosan frameworks. The particle size distribution is shown in Figure , indicating a particle size of 1-7 nm with an average particle size of 2.6 nm. The HR-TEM image of CdS/CTS shows lattice fringes with an interplanar distance of 0.33 nm corresponding to the Miller index plane (111) (Figure ). STEM image indicates the homogenous distribution of CdS QDs inside CTF frameworks (Figure ). The distribution of CdS inside CTS was further confirmed using EDX analysis and mapping (Figure ). The elemental analysis using EDX analysis confirms the presence of elements C, N, O, Cd, and S (Figure ). The elemental distribution of observed elements indicates that Cd is mainly present near CTS functional groups such as NH and OH (Figure ). This observation confirms the results of the XRD, XPS, and HR-TEM images. It also approves that CdS and CTS are a composite, i.e., no mixture. The surface area and pore size distribution of CdS/CTS were characterized using a nitrogen adsorptiondesorption isotherm (Figure , Figure ). The specific surface area and external surface area are evaluated using Brunauer-Emmett-Teller (BET, Figure ) and the t-plot method (BET, Figure ). Data show BET and external specific surface area of 50 m 2 /g. The pore size distribution in CdS/CTS is evaluated using the BJH method (Figure ), DH (Figure ), and DFT (Figure ). Data analysis indicates the presence of a pore size of 1.8-11 nm (Figure ). The porosity of CdS/CTS is created due to the interparticle between CdS and CTS. The material's porosity is improved using freeze-drying. Thermal analysis of CTS, Cd/CTS, and CdS/CTS is evaluated using TGA (Figure ). TGA thermograms of CTS show gradual weight loss due to their organic nature, reaching complete decomposition at 545 o C (Figure ). Cd-coordinated CTS offers higher thermal stability with a metal residual of 5 wt.%. The presence of Cd 2+ ions in the CTS framework improved the thermal stability of CTS. CdS QDs exhibit further improvement in the thermal stability of CTS. The thermal decomposition of CTS was shifted toward a higher temperature by about 60 °C after conjugation with CdS QDs . TGA thermogram of CdS/CTS shows three stages of weight loss: (1) about 13% weight loss from room temperature to 234 °C; (2) 44% weight loss from 250 °C to 464 °C; and (3) 38% weight loss from 464 °C to 526 °C. The first weight-loss stage referred to the evaporation of physically adsorbed molecules such as water. The other weight loss steps are due to the chemisorbed water and residual organics in CdS/CTS. TGA analysis indicates that Cd-coordinated CTS and CdS/CTS composite exhibited higher thermal stability than the pure CTS (Figure ).