There are two approaches to CDs synthesis. The first approach is the top-down method involves laser ablation technique, electrochemical/electro-oxidation process, and shedding or exfoliation of carbon soot. The second approach is the bottom-up approach, such as thermal pyrolysis, microwave irradiation, and hydrothermal/solvothermal treatment [4; 6; 23; 24; 25; 26]. The top-down approach fabricates CDs by way of cleavage of larger carbon structures, such as carbon fibre, carbohydrate, carbon soot, and activated carbon into nanosized carbon particles [27; 28; 29; 30]. The process uses techniques such as ball milling, chemical oxidation [31], lithography/chemical ablation or chemical etching [32], electrochemical oxidation [33], and ultrasonic methods [34]. The bottom-up approach involves the decomposition of a large molecular precursor, and subsequent growth of a nanosized monodispersed colloidal materials from the decomposed molecules [35] as exemplified in polymerization reactions leading to giant molecules from smaller ones. The bottom-up approach leads to the creation of CDs piece by piece in nanoscale size [3; 36; 37; 38; 39]. The synthetic route for the fabrication of CDs reported in literature includes the carbonization of smaller organic molecules through condensation, polymerization, carbonization, and passivation or functionalization with functional groups of choice. The process involves forming chains of small compounds by amidation, aldol condensation, Schiff base condensation, and a radical reaction process. The process leads to the creation of clusters of molecules known as polymerized molecules held by covalent and non-covalent or other dipole-dipole interactions [7; 40]. CDs are fabricated nowadays by green synthesis routes. The process involves using natural materials rich in carbon as the precursors, even though they lack the requisite purity to produce very homogenous CDs [1; 41]. Precursors such as fruits of Platanus biomass [42], banana juice [43], willow back [44], soya milk [45], lemon juice [46], ginkgo fruits juice [47], lychee seed [48], sugar [49], waste papers [41], magnolia flower [50], peels of fresh fruits/vegetables [51], and hemicellulose [52] have been sources of CDs synthesis. Hence, in this research, the synthesis of CDs from palm kernel shell (PKS) doped with ethylenediamine (EDA) and L-phenylalanine (L-Ph) has been explored with the photoluminescence quantum yield studied. Photoluminescence quantum yield is a figure of merit for the optical performance of CDs and fluorophore. It reveals the photon's intensity or nanomaterials' brightness and strength against photobleaching and photostability in its fluorescence application [46; 53; 54]. As shown in Figure 1, PKS consists mainly of cellulose, hemicellulose, and lignin [55; 56]. The thermal reduction of PKS in an inert nitrogen environment converts the cellulose, hemicellulose, and lignin in PKS biomass to a black graphitic carbonaceous material, especially at a temperature above 400 \({}^{\circ}\)C for more than 2 h carbonization time [42; 55; 57]. In this work, CDs were synthesized from the carbonized palm kernel shell (CPKS) using a hydrothermal autoclave technique that offers simplicity and produces spherical CDs of approximately uniform sizes [57; 58]. This study was a green synthesis of CDs based on the non-toxic precursor used to create CDs of high fluorescence and photoluminescence quantum yield for application in biosensor development.